denoland-deno/cli/dts/lib.deno.unstable.d.ts

// Copyright 2018-2022 the Deno authors. All rights reserved. MIT license.

/// <reference no-default-lib="true" />
/// <reference lib="deno.ns" />

declare namespace Deno {
  export {}; // stop default export type behavior

  /** **UNSTABLE**: New API, yet to be vetted.
   *
   * The interface for defining a benchmark test using {@linkcode Deno.bench}.
   *
   * @category Testing
   */
  export interface BenchDefinition {
    /** The test function which will be benchmarked. */
    fn: () => void | Promise<void>;
    /** The name of the test, which will be used in displaying the results. */
    name: string;
    /** If truthy, the benchmark test will be ignored/skipped. */
    ignore?: boolean;
    /** Group name for the benchmark.
     *
     * Grouped benchmarks produce a group time summary, where the difference
     * in performance between each test of the group is compared. */
    group?: string;
    /** Benchmark should be used as the baseline for other benchmarks.
     *
     * If there are multiple baselines in a group, the first one is used as the
     * baseline. */
    baseline?: boolean;
    /** If at least one bench has `only` set to true, only run benches that have
     * `only` set to `true` and fail the bench suite. */
    only?: boolean;
    /** Ensure the bench case does not prematurely cause the process to exit,
     * for example via a call to {@linkcode Deno.exit}. Defaults to `true`. */
    sanitizeExit?: boolean;
    /** Specifies the permissions that should be used to run the bench.
     *
     * Set this to `"inherit"` to keep the calling thread's permissions.
     *
     * Set this to `"none"` to revoke all permissions.
     *
     * Defaults to "inherit".
     */
    permissions?: Deno.PermissionOptions;
  }

  /** **UNSTABLE**: New API, yet to be vetted.
   *
   * Register a benchmark test which will be run when `deno bench` is used on
   * the command line and the containing module looks like a bench module.
   *
   * If the test function (`fn`) returns a promise or is async, the test runner
   * will await resolution to consider the test complete.
   *
   * ```ts
   * import { assertEquals } from "https://deno.land/std/testing/asserts.ts";
   *
   * Deno.bench({
   *   name: "example test",
   *   fn() {
   *     assertEquals("world", "world");
   *   },
   * });
   *
   * Deno.bench({
   *   name: "example ignored test",
   *   ignore: Deno.build.os === "windows",
   *   fn() {
   *     // This test is ignored only on Windows machines
   *   },
   * });
   *
   * Deno.bench({
   *   name: "example async test",
   *   async fn() {
   *     const decoder = new TextDecoder("utf-8");
   *     const data = await Deno.readFile("hello_world.txt");
   *     assertEquals(decoder.decode(data), "Hello world");
   *   }
   * });
   * ```
   *
   * @category Testing
   */
  export function bench(t: BenchDefinition): void;

  /** **UNSTABLE**: New API, yet to be vetted.
   *
   * Register a benchmark test which will be run when `deno bench` is used on
   * the command line and the containing module looks like a bench module.
   *
   * If the test function (`fn`) returns a promise or is async, the test runner
   * will await resolution to consider the test complete.
   *
   * ```ts
   * import { assertEquals } from "https://deno.land/std/testing/asserts.ts";
   *
   * Deno.bench("My test description", () => {
   *   assertEquals("hello", "hello");
   * });
   *
   * Deno.bench("My async test description", async () => {
   *   const decoder = new TextDecoder("utf-8");
   *   const data = await Deno.readFile("hello_world.txt");
   *   assertEquals(decoder.decode(data), "Hello world");
   * });
   * ```
   *
   * @category Testing
   */
  export function bench(
    name: string,
    fn: () => void | Promise<void>,
  ): void;

  /** **UNSTABLE**: New API, yet to be vetted.
   *
   * Register a benchmark test which will be run when `deno bench` is used on
   * the command line and the containing module looks like a bench module.
   *
   * If the test function (`fn`) returns a promise or is async, the test runner
   * will await resolution to consider the test complete.
   *
   * ```ts
   * import { assertEquals } from "https://deno.land/std/testing/asserts.ts";
   *
   * Deno.bench(function myTestName() {
   *   assertEquals("hello", "hello");
   * });
   *
   * Deno.bench(async function myOtherTestName() {
   *   const decoder = new TextDecoder("utf-8");
   *   const data = await Deno.readFile("hello_world.txt");
   *   assertEquals(decoder.decode(data), "Hello world");
   * });
   * ```
   *
   * @category Testing
   */
  export function bench(fn: () => void | Promise<void>): void;

  /** **UNSTABLE**: New API, yet to be vetted.
   *
   * Register a benchmark test which will be run when `deno bench` is used on
   * the command line and the containing module looks like a bench module.
   *
   * If the test function (`fn`) returns a promise or is async, the test runner
   * will await resolution to consider the test complete.
   *
   * ```ts
   * import { assertEquals } from "https://deno.land/std/testing/asserts.ts";
   *
   * Deno.bench(
   *   "My test description",
   *   { permissions: { read: true } },
   *   () => {
   *    assertEquals("hello", "hello");
   *   }
   * );
   *
   * Deno.bench(
   *   "My async test description",
   *   { permissions: { read: false } },
   *   async () => {
   *     const decoder = new TextDecoder("utf-8");
   *     const data = await Deno.readFile("hello_world.txt");
   *     assertEquals(decoder.decode(data), "Hello world");
   *   }
   * );
   * ```
   *
   * @category Testing
   */
  export function bench(
    name: string,
    options: Omit<BenchDefinition, "fn" | "name">,
    fn: () => void | Promise<void>,
  ): void;

  /** **UNSTABLE**: New API, yet to be vetted.
   *
   * Register a benchmark test which will be run when `deno bench` is used on
   * the command line and the containing module looks like a bench module.
   *
   * If the test function (`fn`) returns a promise or is async, the test runner
   * will await resolution to consider the test complete.
   *
   * ```ts
   * import { assertEquals } from "https://deno.land/std/testing/asserts.ts";
   *
   * Deno.bench(
   *   { name: "My test description", permissions: { read: true } },
   *   () => {
   *     assertEquals("hello", "hello");
   *   }
   * );
   *
   * Deno.bench(
   *   { name: "My async test description", permissions: { read: false } },
   *   async () => {
   *     const decoder = new TextDecoder("utf-8");
   *     const data = await Deno.readFile("hello_world.txt");
   *     assertEquals(decoder.decode(data), "Hello world");
   *   }
   * );
   * ```
   *
   * @category Testing
   */
  export function bench(
    options: Omit<BenchDefinition, "fn">,
    fn: () => void | Promise<void>,
  ): void;

  /** **UNSTABLE**: New API, yet to be vetted.
   *
   * Register a benchmark test which will be run when `deno bench` is used on
   * the command line and the containing module looks like a bench module.
   *
   * If the test function (`fn`) returns a promise or is async, the test runner
   * will await resolution to consider the test complete.
   *
   * ```ts
   * import { assertEquals } from "https://deno.land/std/testing/asserts.ts";
   *
   * Deno.bench(
   *   { permissions: { read: true } },
   *   function myTestName() {
   *     assertEquals("hello", "hello");
   *   }
   * );
   *
   * Deno.bench(
   *   { permissions: { read: false } },
   *   async function myOtherTestName() {
   *     const decoder = new TextDecoder("utf-8");
   *     const data = await Deno.readFile("hello_world.txt");
   *     assertEquals(decoder.decode(data), "Hello world");
   *   }
   * );
   * ```
   *
   * @category Testing
   */
  export function bench(
    options: Omit<BenchDefinition, "fn" | "name">,
    fn: () => void | Promise<void>,
  ): void;

  /** **UNSTABLE**: New API, yet to be vetted.
   *
   * Retrieve the process umask.  If `mask` is provided, sets the process umask.
   * This call always returns what the umask was before the call.
   *
   * ```ts
   * console.log(Deno.umask());  // e.g. 18 (0o022)
   * const prevUmaskValue = Deno.umask(0o077);  // e.g. 18 (0o022)
   * console.log(Deno.umask());  // e.g. 63 (0o077)
   * ```
   *
   * This API is under consideration to determine if permissions are required to
   * call it.
   *
   * *Note*: This API is not implemented on Windows
   *
   * @category File System
   */
  export function umask(mask?: number): number;

  /** **UNSTABLE**: New API, yet to be vetted.
   *
   * All plain number types for interfacing with foreign functions.
   *
   * @category FFI
   */
  type NativeNumberType =
    | "u8"
    | "i8"
    | "u16"
    | "i16"
    | "u32"
    | "i32"
    | "f32"
    | "f64";

  /** **UNSTABLE**: New API, yet to be vetted.
   *
   * All BigInt number types for interfacing with foreign functions.
   *
   * @category FFI
   */
  type NativeBigIntType =
    | "u64"
    | "i64"
    | "usize"
    | "isize";

  /** **UNSTABLE**: New API, yet to be vetted.
   *
   * The native boolean type for interfacing to foreign functions.
   *
   * @category FFI
   */
  type NativeBooleanType = "bool";

  /** **UNSTABLE**: New API, yet to be vetted.
   *
   * The native pointer type for interfacing to foreign functions.
   *
   * @category FFI
   */
  type NativePointerType = "pointer";

  /** **UNSTABLE**: New API, yet to be vetted.
   *
   * The native buffer type for interfacing to foreign functions.
   *
   * @category FFI
   */
  type NativeBufferType = "buffer";

  /** **UNSTABLE**: New API, yet to be vetted.
   *
   * The native function type for interfacing with foreign functions.
   *
   * @category FFI
   */
  type NativeFunctionType = "function";

  /** **UNSTABLE**: New API, yet to be vetted.
   *
   * The native void type for interfacing with foreign functions.
   *
   * @category FFI
   */
  type NativeVoidType = "void";

  /** **UNSTABLE**: New API, yet to be vetted.
   *
   * All supported types for interfacing with foreign functions.
   *
   * @category FFI
   */
  export type NativeType =
    | NativeNumberType
    | NativeBigIntType
    | NativeBooleanType
    | NativePointerType
    | NativeBufferType
    | NativeFunctionType;

  /** **UNSTABLE**: New API, yet to be vetted.
   *
   * @category FFI
   */
  export type NativeResultType = NativeType | NativeVoidType;

  /** **UNSTABLE**: New API, yet to be vetted.
   *
   * A utility type conversion for foreign symbol parameters and unsafe callback
   * return types.
   *
   * @category FFI
   */
  type ToNativeTypeMap =
    & Record<NativeNumberType, number>
    & Record<NativeBigIntType, PointerValue>
    & Record<NativeBooleanType, boolean>
    & Record<NativePointerType, PointerValue | null>
    & Record<NativeFunctionType, PointerValue | null>
    & Record<NativeBufferType, BufferSource | null>;

  /** **UNSTABLE**: New API, yet to be vetted.
   *
   * Type conversion for foreign symbol parameters and unsafe callback return
   * types.
   *
   * @category FFI
   */
  type ToNativeType<T extends NativeType = NativeType> = ToNativeTypeMap[T];

  /** **UNSTABLE**: New API, yet to be vetted.
   *
   * A utility type for conversion for unsafe callback return types.
   *
   * @category FFI
   */
  type ToNativeResultTypeMap = ToNativeTypeMap & Record<NativeVoidType, void>;

  /** **UNSTABLE**: New API, yet to be vetted.
   *
   * Type conversion for unsafe callback return types.
   *
   * @category FFI
   */
  type ToNativeResultType<T extends NativeResultType = NativeResultType> =
    ToNativeResultTypeMap[T];

  /** **UNSTABLE**: New API, yet to be vetted.
   *
   * A utility type for conversion of parameter types of foreign functions.
   *
   * @category FFI
   */
  type ToNativeParameterTypes<T extends readonly NativeType[]> =
    //
    [(T[number])[]] extends [T] ? ToNativeType<T[number]>[]
      : [readonly (T[number])[]] extends [T]
        ? readonly ToNativeType<T[number]>[]
      : T extends readonly [...NativeType[]] ? {
          [K in keyof T]: ToNativeType<T[K]>;
        }
      : never;

  /** **UNSTABLE**: New API, yet to be vetted.
   *
   * A utility type for conversion of foreign symbol return types and unsafe
   * callback parameters.
   *
   * @category FFI
   */
  type FromNativeTypeMap =
    & Record<NativeNumberType, number>
    & Record<NativeBigIntType, PointerValue>
    & Record<NativeBooleanType, boolean>
    & Record<NativePointerType, PointerValue>
    & Record<NativeBufferType, PointerValue>
    & Record<NativeFunctionType, PointerValue>;

  /** **UNSTABLE**: New API, yet to be vetted.
   *
   * Type conversion for foreign symbol return types and unsafe callback
   * parameters.
   *
   * @category FFI
   */
  type FromNativeType<T extends NativeType = NativeType> = FromNativeTypeMap[T];

  /** **UNSTABLE**: New API, yet to be vetted.
   *
   * A utility type for conversion for foreign symbol return types.
   *
   * @category FFI
   */
  type FromNativeResultTypeMap =
    & FromNativeTypeMap
    & Record<NativeVoidType, void>;

  /** **UNSTABLE**: New API, yet to be vetted.
   *
   * Type conversion for foreign symbol return types.
   *
   * @category FFI
   */
  type FromNativeResultType<T extends NativeResultType = NativeResultType> =
    FromNativeResultTypeMap[T];

  /** **UNSTABLE**: New API, yet to be vetted.
   *
   * @category FFI
   */
  type FromNativeParameterTypes<
    T extends readonly NativeType[],
  > =
    //
    [(T[number])[]] extends [T] ? FromNativeType<T[number]>[]
      : [readonly (T[number])[]] extends [T]
        ? readonly FromNativeType<T[number]>[]
      : T extends readonly [...NativeType[]] ? {
          [K in keyof T]: FromNativeType<T[K]>;
        }
      : never;

  /** **UNSTABLE**: New API, yet to be vetted.
   *
   * The interface for a foreign function as defined by its parameter and result
   * types.
   *
   * @category FFI
   */
  export interface ForeignFunction<
    Parameters extends readonly NativeType[] = readonly NativeType[],
    Result extends NativeResultType = NativeResultType,
    NonBlocking extends boolean = boolean,
  > {
    /** Name of the symbol.
     *
     * Defaults to the key name in symbols object. */
    name?: string;
    /** The parameters of the foreign function. */
    parameters: Parameters;
    /** The result (return value) of the foreign function. */
    result: Result;
    /** When `true`, function calls will run on a dedicated blocking thread and
     * will return a `Promise` resolving to the `result`. */
    nonblocking?: NonBlocking;
    /** When `true`, function calls can safely callback into JavaScript or
     * trigger a garbage collection event.
     *
     * Default is `false`. */
    callback?: boolean;
  }

  /** **UNSTABLE**: New API, yet to be vetted.
   *
   * @category FFI
   */
  export interface ForeignStatic<Type extends NativeType = NativeType> {
    /** Name of the symbol, defaults to the key name in symbols object. */
    name?: string;
    /** The type of the foreign static value. */
    type: Type;
  }

  /** **UNSTABLE**: New API, yet to be vetted.
   *
   * A foreign library interface descriptor.
   *
   * @category FFI
   */
  export interface ForeignLibraryInterface {
    [name: string]: ForeignFunction | ForeignStatic;
  }

  /** **UNSTABLE**: New API, yet to be vetted.
   *
   * A utility type that infers a foreign symbol.
   *
   * @category FFI
   */
  type StaticForeignSymbol<T extends ForeignFunction | ForeignStatic> =
    T extends ForeignFunction ? FromForeignFunction<T>
      : T extends ForeignStatic ? FromNativeType<T["type"]>
      : never;

  /** **UNSTABLE**: New API, yet to be vetted.
   *
   *  @category FFI
   */
  type FromForeignFunction<T extends ForeignFunction> = T["parameters"] extends
    readonly [] ? () => StaticForeignSymbolReturnType<T>
    : (
      ...args: ToNativeParameterTypes<T["parameters"]>
    ) => StaticForeignSymbolReturnType<T>;

  /** **UNSTABLE**: New API, yet to be vetted.
   *
   * @category FFI
   */
  type StaticForeignSymbolReturnType<T extends ForeignFunction> =
    ConditionalAsync<T["nonblocking"], FromNativeResultType<T["result"]>>;

  /** **UNSTABLE**: New API, yet to be vetted.
   *
   * @category FFI
   */
  type ConditionalAsync<IsAsync extends boolean | undefined, T> =
    IsAsync extends true ? Promise<T> : T;

  /** **UNSTABLE**: New API, yet to be vetted.
   *
   * A utility type that infers a foreign library interface.
   *
   * @category FFI
   */
  type StaticForeignLibraryInterface<T extends ForeignLibraryInterface> = {
    [K in keyof T]: StaticForeignSymbol<T[K]>;
  };

  /** **UNSTABLE**: New API, yet to be vetted.
   *
   * Pointer type depends on the architecture and actual pointer value.
   *
   * On a 32 bit host system all pointer values are plain numbers. On a 64 bit
   * host system pointer values are represented as numbers if the value is below
   * `Number.MAX_SAFE_INTEGER`, otherwise they are provided as bigints.
   *
   * @category FFI
   */
  export type PointerValue = number | bigint;

  /** **UNSTABLE**: New API, yet to be vetted.
   *
   * An unsafe pointer to a memory location for passing and returning pointers
   * to and from the FFI.
   *
   * @category FFI
   */
  export class UnsafePointer {
    /** Return the direct memory pointer to the typed array in memory. */
    static of(value: Deno.UnsafeCallback | BufferSource): PointerValue;
  }

  /** **UNSTABLE**: New API, yet to be vetted.
   *
   * An unsafe pointer view to a memory location as specified by the `pointer`
   * value. The `UnsafePointerView` API follows the standard built in interface
   * {@linkcode DataView} for accessing the underlying types at an memory
   * location (numbers, strings and raw bytes).
   *
   * @category FFI
   */
  export class UnsafePointerView {
    constructor(pointer: PointerValue);

    pointer: PointerValue;

    /** Gets a boolean at the specified byte offset from the pointer. */
    getBool(offset?: number): boolean;
    /** Gets an unsigned 8-bit integer at the specified byte offset from the
     * pointer. */
    getUint8(offset?: number): number;
    /** Gets a signed 8-bit integer at the specified byte offset from the
     * pointer. */
    getInt8(offset?: number): number;
    /** Gets an unsigned 16-bit integer at the specified byte offset from the
     * pointer. */
    getUint16(offset?: number): number;
    /** Gets a signed 16-bit integer at the specified byte offset from the
     * pointer. */
    getInt16(offset?: number): number;
    /** Gets an unsigned 32-bit integer at the specified byte offset from the
     * pointer. */
    getUint32(offset?: number): number;
    /** Gets a signed 32-bit integer at the specified byte offset from the
     * pointer. */
    getInt32(offset?: number): number;
    /** Gets an unsigned 64-bit integer at the specified byte offset from the
     * pointer. */
    getBigUint64(offset?: number): PointerValue;
    /** Gets a signed 64-bit integer at the specified byte offset from the
     * pointer. */
    getBigInt64(offset?: number): PointerValue;
    /** Gets a signed 32-bit float at the specified byte offset from the
     * pointer. */
    getFloat32(offset?: number): number;
    /** Gets a signed 64-bit float at the specified byte offset from the
     * pointer. */
    getFloat64(offset?: number): number;
    /** Gets a C string (`null` terminated string) at the specified byte offset
     * from the pointer. */
    getCString(offset?: number): string;
    /** Gets a C string (`null` terminated string) at the specified byte offset
     * from the specified pointer. */
    static getCString(pointer: PointerValue, offset?: number): string;
    /** Gets an `ArrayBuffer` of length `byteLength` at the specified byte
     * offset from the pointer. */
    getArrayBuffer(byteLength: number, offset?: number): ArrayBuffer;
    /** Gets an `ArrayBuffer` of length `byteLength` at the specified byte
     * offset from the specified pointer. */
    static getArrayBuffer(
      pointer: PointerValue,
      byteLength: number,
      offset?: number,
    ): ArrayBuffer;
    /** Copies the memory of the pointer into a typed array.
     *
     * Length is determined from the typed array's `byteLength`.
     *
     * Also takes optional byte offset from the pointer. */
    copyInto(destination: BufferSource, offset?: number): void;
    /** Copies the memory of the specified pointer into a typed array.
     *
     * Length is determined from the typed array's `byteLength`.
     *
     * Also takes optional byte offset from the pointer. */
    static copyInto(
      pointer: PointerValue,
      destination: BufferSource,
      offset?: number,
    ): void;
  }

  /** **UNSTABLE**: New API, yet to be vetted.
   *
   * An unsafe pointer to a function, for calling functions that are not present
   * as symbols.
   *
   * @category FFI
   */
  export class UnsafeFnPointer<Fn extends ForeignFunction> {
    /** The pointer to the function. */
    pointer: PointerValue;
    /** The definition of the function. */
    definition: Fn;

    constructor(pointer: PointerValue, definition: Fn);

    /** Call the foreign function. */
    call: FromForeignFunction<Fn>;
  }

  /** **UNSTABLE**: New API, yet to be vetted.
   *
   * Definition of a unsafe callback function.
   *
   * @category FFI
   */
  export interface UnsafeCallbackDefinition<
    Parameters extends readonly NativeType[] = readonly NativeType[],
    Result extends NativeResultType = NativeResultType,
  > {
    /** The parameters of the callbacks. */
    parameters: Parameters;
    /** The current result of the callback. */
    result: Result;
  }

  /** **UNSTABLE**: New API, yet to be vetted.
   *
   * An unsafe callback function.
   *
   * @category FFI
   */
  type UnsafeCallbackFunction<
    Parameters extends readonly NativeType[] = readonly NativeType[],
    Result extends NativeResultType = NativeResultType,
  > = Parameters extends readonly [] ? () => ToNativeResultType<Result> : (
    ...args: FromNativeParameterTypes<Parameters>
  ) => ToNativeResultType<Result>;

  /** **UNSTABLE**: New API, yet to be vetted.
   *
   * An unsafe function pointer for passing JavaScript functions as C function
   * pointers to foreign function calls.
   *
   * The function pointer remains valid until the `close()` method is called.
   *
   * The callback can be explicitly referenced via `ref()` and dereferenced via
   * `deref()` to stop Deno's process from exiting.
   *
   * @category FFI
   */
  export class UnsafeCallback<
    Definition extends UnsafeCallbackDefinition = UnsafeCallbackDefinition,
  > {
    constructor(
      definition: Definition,
      callback: UnsafeCallbackFunction<
        Definition["parameters"],
        Definition["result"]
      >,
    );

    /** The pointer to the unsafe callback. */
    pointer: PointerValue;
    /** The definition of the unsafe callback. */
    definition: Definition;
    /** The callback function. */
    callback: UnsafeCallbackFunction<
      Definition["parameters"],
      Definition["result"]
    >;

    /**
     * Adds one to this callback's reference counting and returns the new
     * reference count.
     *
     * If the callback's reference count is non-zero, it will keep Deno's
     * process from exiting.
     */
    ref(): number;

    /**
     * Removes one from this callback's reference counting and returns the new
     * reference count.
     *
     * If the callback's reference counter is zero, it will no longer keep
     * Deno's process from exiting.
     */
    unref(): number;

    /**
     * Removes the C function pointer associated with this instance.
     *
     * Continuing to use the instance after calling this object will lead to
     * errors and crashes.
     *
     * Calling this method will also immediately set the callback's reference
     * counting to zero and it will no longer keep Deno's process from exiting.
     */
    close(): void;
  }

  /** **UNSTABLE**: New API, yet to be vetted.
   *
   * A dynamic library resource.  Use {@linkcode Deno.dlopen} to load a dynamic
   * library and return this interface.
   *
   * @category FFI
   */
  export interface DynamicLibrary<S extends ForeignLibraryInterface> {
    /** All of the registered library along with functions for calling them. */
    symbols: StaticForeignLibraryInterface<S>;
    /** Removes the pointers associated with the library symbols.
     *
     * Continuing to use symbols that are part of the library will lead to
     * errors and crashes.
     *
     * Calling this method will also immediately set any references to zero and
     * will no longer keep Deno's process from exiting.
     */
    close(): void;
  }

  /** **UNSTABLE**: New API, yet to be vetted.
   *
   * Opens an external dynamic library and registers symbols, making foreign
   * functions available to be called.
   *
   * Requires `allow-ffi` permission. Loading foreign dynamic libraries can in
   * theory bypass all of the sandbox permissions. While it is a separate
   * permission users should acknowledge in practice that is effectively the
   * same as running with the `allow-all` permission.
   *
   * An example, given a C library which exports a foreign function named
   * `add()`:
   *
   * ```ts
   * // Determine library extension based on
   * // your OS.
   * let libSuffix = "";
   * switch (Deno.build.os) {
   *   case "windows":
   *     libSuffix = "dll";
   *     break;
   *   case "darwin":
   *     libSuffix = "dylib";
   *     break;
   *   default:
   *     libSuffix = "so";
   *     break;
   * }
   *
   * const libName = `./libadd.${libSuffix}`;
   * // Open library and define exported symbols
   * const dylib = Deno.dlopen(
   *   libName,
   *   {
   *     "add": { parameters: ["isize", "isize"], result: "isize" },
   *   } as const,
   * );
   *
   * // Call the symbol `add`
   * const result = dylib.symbols.add(35, 34); // 69
   *
   * console.log(`Result from external addition of 35 and 34: ${result}`);
   * ```
   *
   * @tags allow-ffi
   * @category FFI
   */
  export function dlopen<S extends ForeignLibraryInterface>(
    filename: string | URL,
    symbols: S,
  ): DynamicLibrary<S>;

  /** **UNSTABLE**: New API, yet to be vetted.
   *
   * These are unstable options which can be used with {@linkcode Deno.run}.
   */
  interface UnstableRunOptions extends RunOptions {
    /** If `true`, clears the environment variables before executing the
     * sub-process.  Defaults to `false`. */
    clearEnv?: boolean;
    /** For POSIX systems, sets the group ID for the sub process. */
    gid?: number;
    /** For POSIX systems, sets the user ID for the sub process. */
    uid?: number;
  }

  /** **UNSTABLE**: New API, yet to be vetted.
   *
   * Spawns new subprocess. RunOptions must contain at a minimum the `opt.cmd`,
   * an array of program arguments, the first of which is the binary.
   *
   * ```ts
   * const p = Deno.run({
   *   cmd: ["curl", "https://example.com"],
   * });
   * const status = await p.status();
   * ```
   *
   * Subprocess uses same working directory as parent process unless `opt.cwd`
   * is specified.
   *
   * Environmental variables from parent process can be cleared using `opt.clearEnv`.
   * Doesn't guarantee that only `opt.env` variables are present,
   * as the OS may set environmental variables for processes.
   *
   * Environmental variables for subprocess can be specified using `opt.env`
   * mapping.
   *
   * `opt.uid` sets the child process’s user ID. This translates to a setuid call
   * in the child process. Failure in the setuid call will cause the spawn to fail.
   *
   * `opt.gid` is similar to `opt.uid`, but sets the group ID of the child process.
   * This has the same semantics as the uid field.
   *
   * By default subprocess inherits stdio of parent process. To change
   * this this, `opt.stdin`, `opt.stdout`, and `opt.stderr` can be set
   * independently to a resource ID (_rid_) of an open file, `"inherit"`,
   * `"piped"`, or `"null"`:
   *
   * - _number_: the resource ID of an open file/resource. This allows you to
   *   read or write to a file.
   * - `"inherit"`: The default if unspecified. The subprocess inherits from the
   *   parent.
   * - `"piped"`: A new pipe should be arranged to connect the parent and child
   *   sub-process.
   * - `"null"`: This stream will be ignored. This is the equivalent of attaching
   *   the stream to `/dev/null`.
   *
   * Details of the spawned process are returned as an instance of
   * {@linkcode Deno.Process}.
   *
   * Requires `allow-run` permission.
   *
   * @tags allow-run
   * @category Sub Process
   */
  export function run<T extends UnstableRunOptions = UnstableRunOptions>(
    opt: T,
  ): Process<T>;

  /** **UNSTABLE**: New API, yet to be vetted.
   *
   * A custom `HttpClient` for use with {@linkcode fetch} function. This is
   * designed to allow custom certificates or proxies to be used with `fetch()`.
   *
   * ```ts
   * const caCert = await Deno.readTextFile("./ca.pem");
   * const client = Deno.createHttpClient({ caCerts: [ caCert ] });
   * const req = await fetch("https://myserver.com", { client });
   * ```
   *
   * @category Fetch API
   */
  export interface HttpClient {
    /** The resource ID associated with the client. */
    rid: number;
    /** Close the HTTP client. */
    close(): void;
  }

  /** **UNSTABLE**: New API, yet to be vetted.
   *
   * The options used when creating a {@linkcode Deno.HttpClient}.
   *
   * @category Fetch API
   */
  export interface CreateHttpClientOptions {
    /** A list of root certificates that will be used in addition to the
     * default root certificates to verify the peer's certificate.
     *
     * Must be in PEM format. */
    caCerts?: string[];
    /** A HTTP proxy to use for new connections. */
    proxy?: Proxy;
    /** PEM formatted client certificate chain. */
    certChain?: string;
    /** PEM formatted (RSA or PKCS8) private key of client certificate. */
    privateKey?: string;
  }

  /** **UNSTABLE**: New API, yet to be vetted.
   *
   * The definition of a proxy when specifying
   * {@linkcode Deno.CreateHttpClientOptions}.
   *
   * @category Fetch API
   */
  export interface Proxy {
    /** The string URL of the proxy server to use. */
    url: string;
    /** The basic auth credentials to be used against the proxy server. */
    basicAuth?: BasicAuth;
  }

  /** **UNSTABLE**: New API, yet to be vetted.
   *
   * Basic authentication credentials to be used with a {@linkcode Deno.Proxy}
   * server when specifying {@linkcode Deno.CreateHttpClientOptions}.
   *
   * @category Fetch API
   */
  export interface BasicAuth {
    /** The username to be used against the proxy server. */
    username: string;
    /** The password to be used against the proxy server. */
    password: string;
  }

  /** **UNSTABLE**: New API, yet to be vetted.
   *
   * Create a custom HttpClient for to use with {@linkcode fetch}. This is an
   * extension of the web platform Fetch API which allows Deno to use custom
   * TLS certificates and connect via a proxy while using `fetch()`.
   *
   * ```ts
   * const caCert = await Deno.readTextFile("./ca.pem");
   * const client = Deno.createHttpClient({ caCerts: [ caCert ] });
   * const response = await fetch("https://myserver.com", { client });
   * ```
   *
   * ```ts
   * const client = Deno.createHttpClient({
   *   proxy: { url: "http://myproxy.com:8080" }
   * });
   * const response = await fetch("https://myserver.com", { client });
   * ```
   *
   * @category Fetch API
   */
  export function createHttpClient(
    options: CreateHttpClientOptions,
  ): HttpClient;

  /** **UNSTABLE**: New API, yet to be vetted.
   *
   * A generic transport listener for message-oriented protocols.
   *
   * @category Network
   */
  export interface DatagramConn extends AsyncIterable<[Uint8Array, Addr]> {
    /** Waits for and resolves to the next message to the instance.
     *
     * Messages are received in the format of a tuple containing the data array
     * and the address information.
     */
    receive(p?: Uint8Array): Promise<[Uint8Array, Addr]>;
    /** Sends a message to the target via the connection. The method resolves
     * with the number of bytes sent. */
    send(p: Uint8Array, addr: Addr): Promise<number>;
    /** Close closes the socket. Any pending message promises will be rejected
     * with errors. */
    close(): void;
    /** Return the address of the instance. */
    readonly addr: Addr;
    [Symbol.asyncIterator](): AsyncIterableIterator<[Uint8Array, Addr]>;
  }

  /**
   * @category Network
   */
  export interface TcpListenOptions extends ListenOptions {
    /** When `true` the SO_REUSEPORT flag will be set on the listener. This
     * allows multiple processes to listen on the same address and port.
     *
     * On Linux this will cause the kernel to distribute incoming connections
     * across the different processes that are listening on the same address and
     * port.
     *
     * This flag is only supported on Linux. It is silently ignored on other
     * platforms. Defaults to `false`. */
    reusePort?: boolean;
  }

  /** **UNSTABLE**: New API, yet to be vetted.
   *
   * Unstable options which can be set when opening a Unix listener via
   * {@linkcode Deno.listen} or {@linkcode Deno.listenDatagram}.
   *
   * @category Network
   */
  export interface UnixListenOptions {
    /** A path to the Unix Socket. */
    path: string;
  }

  /** **UNSTABLE**: New API, yet to be vetted.
   *
   * Unstable options which can be set when opening a datagram listener via
   * {@linkcode Deno.listenDatagram}.
   *
   * @category Network
   */
  export interface UdpListenOptions extends ListenOptions {
    /** When `true` the specified address will be reused, even if another
     * process has already bound a socket on it. This effectively steals the
     * socket from the listener.
     *
     * Defaults to `false`. */
    reuseAddress?: boolean;
  }

  /** **UNSTABLE**: New API, yet to be vetted.
   *
   * Listen announces on the local transport address.
   *
   * ```ts
   * const listener = Deno.listen({ path: "/foo/bar.sock", transport: "unix" })
   * ```
   *
   * Requires `allow-read` and `allow-write` permission.
   *
   * @tags allow-read, allow-write
   * @category Network
   */
  export function listen(
    options: UnixListenOptions & { transport: "unix" },
  ): Listener;

  /** **UNSTABLE**: New API, yet to be vetted.
   *
   * Listen announces on the local transport address.
   *
   * ```ts
   * const listener1 = Deno.listenDatagram({
   *   port: 80,
   *   transport: "udp"
   * });
   * const listener2 = Deno.listenDatagram({
   *   hostname: "golang.org",
   *   port: 80,
   *   transport: "udp"
   * });
   * ```
   *
   * Requires `allow-net` permission.
   *
   * @tags allow-net
   * @category Network
   */
  export function listenDatagram(
    options: UdpListenOptions & { transport: "udp" },
  ): DatagramConn;

  /** **UNSTABLE**: New API, yet to be vetted.
   *
   * Listen announces on the local transport address.
   *
   * ```ts
   * const listener = Deno.listenDatagram({
   *   path: "/foo/bar.sock",
   *   transport: "unixpacket"
   * });
   * ```
   *
   * Requires `allow-read` and `allow-write` permission.
   *
   * @tags allow-read, allow-write
   * @category Network
   */
  export function listenDatagram(
    options: UnixListenOptions & { transport: "unixpacket" },
  ): DatagramConn;

  /** **UNSTABLE**: New API, yet to be vetted.
   *
   * @category Network
   */
  export interface UnixConnectOptions {
    transport: "unix";
    path: string;
  }

  /** **UNSTABLE**: New API, yet to be vetted.
   *
   * Connects to the hostname (default is "127.0.0.1") and port on the named
   * transport (default is "tcp"), and resolves to the connection (`Conn`).
   *
   * ```ts
   * const conn1 = await Deno.connect({ port: 80 });
   * const conn2 = await Deno.connect({ hostname: "192.0.2.1", port: 80 });
   * const conn3 = await Deno.connect({ hostname: "[2001:db8::1]", port: 80 });
   * const conn4 = await Deno.connect({ hostname: "golang.org", port: 80, transport: "tcp" });
   * const conn5 = await Deno.connect({ path: "/foo/bar.sock", transport: "unix" });
   * ```
   *
   * Requires `allow-net` permission for "tcp" and `allow-read` for "unix".
   *
   * @tags allow-net, allow-read
   * @category Network
   */
  export function connect(options: ConnectOptions): Promise<TcpConn>;
  /** **UNSTABLE**: New API, yet to be vetted.
   *
   * Connects to the hostname (default is "127.0.0.1") and port on the named
   * transport (default is "tcp"), and resolves to the connection (`Conn`).
   *
   * ```ts
   * const conn1 = await Deno.connect({ port: 80 });
   * const conn2 = await Deno.connect({ hostname: "192.0.2.1", port: 80 });
   * const conn3 = await Deno.connect({ hostname: "[2001:db8::1]", port: 80 });
   * const conn4 = await Deno.connect({ hostname: "golang.org", port: 80, transport: "tcp" });
   * const conn5 = await Deno.connect({ path: "/foo/bar.sock", transport: "unix" });
   * ```
   *
   * Requires `allow-net` permission for "tcp" and `allow-read` for "unix".
   *
   * @tags allow-net, allow-read
   * @category Network
   */
  export function connect(options: UnixConnectOptions): Promise<UnixConn>;

  /** **UNSTABLE**: New API, yet to be vetted.
   *
   * @category Network
   */
  export interface ConnectTlsOptions {
    /** **UNSTABLE**: New API, yet to be vetted.
     *
     * PEM formatted client certificate chain.
     */
    certChain?: string;
    /** **UNSTABLE**: New API, yet to be vetted.
     *
     * PEM formatted (RSA or PKCS8) private key of client certificate.
     */
    privateKey?: string;
    /** **UNSTABLE**: New API, yet to be vetted.
     *
     * Application-Layer Protocol Negotiation (ALPN) protocols supported by
     * the client. If not specified, no ALPN extension will be included in the
     * TLS handshake.
     */
    alpnProtocols?: string[];
  }

  /** **UNSTABLE**: New API, yet to be vetted.
   *
   * @category Network
   */
  export interface TlsHandshakeInfo {
    /** **UNSTABLE**: New API, yet to be vetted.
     *
     * Contains the ALPN protocol selected during negotiation with the server.
     * If no ALPN protocol selected, returns `null`.
     */
    alpnProtocol: string | null;
  }

  /** **UNSTABLE**: New API, yet to be vetted.
   *
   * @category Network
   */
  export interface TlsConn extends Conn {
    /** **UNSTABLE**: New API, yet to be vetted.
     *
     * Runs the client or server handshake protocol to completion if that has
     * not happened yet. Calling this method is optional; the TLS handshake
     * will be completed automatically as soon as data is sent or received.
     */
    handshake(): Promise<TlsHandshakeInfo>;
  }

  /** **UNSTABLE**: New API, yet to be vetted.
   *
   * Create a TLS connection with an attached client certificate.
   *
   * ```ts
   * const conn = await Deno.connectTls({
   *   hostname: "deno.land",
   *   port: 443,
   *   certChain: "---- BEGIN CERTIFICATE ----\n ...",
   *   privateKey: "---- BEGIN PRIVATE KEY ----\n ...",
   * });
   * ```
   *
   * Requires `allow-net` permission.
   *
   * @tags allow-net
   * @category Network
   */
  export function connectTls(options: ConnectTlsOptions): Promise<TlsConn>;

  /** **UNSTABLE**: New API, yet to be vetted.
   *
   * @category Network
   */
  export interface ListenTlsOptions {
    /** **UNSTABLE**: New API, yet to be vetted.
     *
     * Application-Layer Protocol Negotiation (ALPN) protocols to announce to
     * the client. If not specified, no ALPN extension will be included in the
     * TLS handshake.
     */
    alpnProtocols?: string[];
  }

  /** **UNSTABLE**: New API, yet to be vetted.
   *
   * @category Network
   */
  export interface StartTlsOptions {
    /** **UNSTABLE**: New API, yet to be vetted.
     *
     * Application-Layer Protocol Negotiation (ALPN) protocols to announce to
     * the client. If not specified, no ALPN extension will be included in the
     * TLS handshake.
     */
    alpnProtocols?: string[];
  }

  /** @category Network */
  export interface Listener extends AsyncIterable<Conn> {
    /** **UNSTABLE**: New API, yet to be vetted.
     *
     * Make the listener block the event loop from finishing.
     *
     * Note: the listener blocks the event loop from finishing by default.
     * This method is only meaningful after `.unref()` is called.
     */
    ref(): void;
    /** **UNSTABLE**: New API, yet to be vetted.
     *
     * Make the listener not block the event loop from finishing.
     */
    unref(): void;
  }

  /** **UNSTABLE**: New API, yet to be vetted.
   *
   * Acquire an advisory file-system lock for the provided file. `exclusive`
   * defaults to `false`.
   *
   * @category File System
   */
  export function flock(rid: number, exclusive?: boolean): Promise<void>;

  /** **UNSTABLE**: New API, yet to be vetted.
   *
   * Acquire an advisory file-system lock synchronously for the provided file.
   * `exclusive` defaults to `false`.
   *
   * @category File System
   */
  export function flockSync(rid: number, exclusive?: boolean): void;

  /** **UNSTABLE**: New API, yet to be vetted.
   *
   * Release an advisory file-system lock for the provided file.
   *
   * @category File System
   */
  export function funlock(rid: number): Promise<void>;

  /** **UNSTABLE**: New API, yet to be vetted.
   *
   * Release an advisory file-system lock for the provided file synchronously.
   *
   * @category File System
   */
  export function funlockSync(rid: number): void;

  /** **UNSTABLE**: New API, yet to be vetted.
   *
   * A handler for HTTP requests. Consumes a request and returns a response.
   *
   * If a handler throws, the server calling the handler will assume the impact
   * of the error is isolated to the individual request. It will catch the error
   * and if necessary will close the underlying connection.
   *
   * @category HTTP Server
   */
  export type ServeHandler = (request: Request) => Response | Promise<Response>;

  /** **UNSTABLE**: New API, yet to be vetted.
   *
   * Options which can be set when calling {@linkcode Deno.serve}.
   *
   * @category HTTP Server
   */
  export interface ServeOptions extends Partial<Deno.ListenOptions> {
    /** An {@linkcode AbortSignal} to close the server and all connections. */
    signal?: AbortSignal;

    /** Sets `SO_REUSEPORT` on POSIX systems. */
    reusePort?: boolean;

    /** The handler to invoke when route handlers throw an error. */
    onError?: (error: unknown) => Response | Promise<Response>;

    /** The callback which is called when the server starts listening. */
    onListen?: (params: { hostname: string; port: number }) => void;
  }

  /** **UNSTABLE**: New API, yet to be vetted.
   *
   * Additional options which are used when opening a TLS (HTTPS) server.
   *
   * @category HTTP Server
   */
  export interface ServeTlsOptions extends ServeOptions {
    /** Server private key in PEM format */
    cert: string;

    /** Cert chain in PEM format */
    key: string;
  }

  /** **UNSTABLE**: New API, yet to be vetted.
   *
   * @category HTTP Server
   */
  export interface ServeInit {
    /** The handler to invoke to process each incoming request. */
    handler: ServeHandler;
  }

  /** **UNSTABLE**: New API, yet to be vetted.
   *
   * Serves HTTP requests with the given handler.
   *
   * You can specify an object with a port and hostname option, which is the
   * address to listen on. The default is port `9000` on hostname `"127.0.0.1"`.
   *
   * The below example serves with the port `9000`.
   *
   * ```ts
   * Deno.serve((_req) => new Response("Hello, world"));
   * ```
   *
   * You can change the address to listen on using the `hostname` and `port`
   * options. The below example serves on port `3000`.
   *
   * ```ts
   * Deno.serve({ port: 3000 }, (_req) => new Response("Hello, world"));
   * ```
   *
   * You can stop the server with an {@linkcode AbortSignal}. The abort signal
   * needs to be passed as the `signal` option in the options bag. The server
   * aborts when the abort signal is aborted. To wait for the server to close,
   * await the promise returned from the `Deno.serve` API.
   *
   * ```ts
   * const ac = new AbortController();
   *
   * Deno.serve({ signal: ac.signal }, (_req) => new Response("Hello, world"))
   *  .then(() => console.log("Server closed"));
   *
   * console.log("Closing server...");
   * ac.abort();
   * ```
   *
   * By default `Deno.serve` prints the message
   * `Listening on http://<hostname>:<port>/` on listening. If you like to
   * change this behavior, you can specify a custom `onListen` callback.
   *
   * ```ts
   * Deno.serve({
   *   onListen({ port, hostname }) {
   *     console.log(`Server started at http://${hostname}:${port}`);
   *     // ... more info specific to your server ..
   *   },
   *   handler: (_req) => new Response("Hello, world"),
   * });
   * ```
   *
   * To enable TLS you must specify the `key` and `cert` options.
   *
   * ```ts
   * const cert = "-----BEGIN CERTIFICATE-----\n...\n-----END CERTIFICATE-----\n";
   * const key = "-----BEGIN PRIVATE KEY-----\n...\n-----END PRIVATE KEY-----\n";
   * Deno.serve({ cert, key }, (_req) => new Response("Hello, world"));
   * ```
   *
   * @category HTTP Server
   */
  export function serve(
    handler: ServeHandler,
    options?: ServeOptions | ServeTlsOptions,
  ): Promise<void>;
  /** **UNSTABLE**: New API, yet to be vetted.
   *
   * Serves HTTP requests with the given handler.
   *
   * You can specify an object with a port and hostname option, which is the
   * address to listen on. The default is port `9000` on hostname `"127.0.0.1"`.
   *
   * The below example serves with the port `9000`.
   *
   * ```ts
   * Deno.serve((_req) => new Response("Hello, world"));
   * ```
   *
   * You can change the address to listen on using the `hostname` and `port`
   * options. The below example serves on port `3000`.
   *
   * ```ts
   * Deno.serve({ port: 3000 }, (_req) => new Response("Hello, world"));
   * ```
   *
   * You can stop the server with an {@linkcode AbortSignal}. The abort signal
   * needs to be passed as the `signal` option in the options bag. The server
   * aborts when the abort signal is aborted. To wait for the server to close,
   * await the promise returned from the `Deno.serve` API.
   *
   * ```ts
   * const ac = new AbortController();
   *
   * Deno.serve({ signal: ac.signal }, (_req) => new Response("Hello, world"))
   *  .then(() => console.log("Server closed"));
   *
   * console.log("Closing server...");
   * ac.abort();
   * ```
   *
   * By default `Deno.serve` prints the message
   * `Listening on http://<hostname>:<port>/` on listening. If you like to
   * change this behavior, you can specify a custom `onListen` callback.
   *
   * ```ts
   * Deno.serve({
   *   onListen({ port, hostname }) {
   *     console.log(`Server started at http://${hostname}:${port}`);
   *     // ... more info specific to your server ..
   *   },
   *   handler: (_req) => new Response("Hello, world"),
   * });
   * ```
   *
   * To enable TLS you must specify the `key` and `cert` options.
   *
   * ```ts
   * const cert = "-----BEGIN CERTIFICATE-----\n...\n-----END CERTIFICATE-----\n";
   * const key = "-----BEGIN PRIVATE KEY-----\n...\n-----END PRIVATE KEY-----\n";
   * Deno.serve({ cert, key }, (_req) => new Response("Hello, world"));
   * ```
   *
   * @category HTTP Server
   */
  export function serve(
    options: ServeOptions | ServeTlsOptions,
    handler: ServeHandler,
  ): Promise<void>;
  /** **UNSTABLE**: New API, yet to be vetted.
   *
   * Serves HTTP requests with the given handler.
   *
   * You can specify an object with a port and hostname option, which is the
   * address to listen on. The default is port `9000` on hostname `"127.0.0.1"`.
   *
   * The below example serves with the port `9000`.
   *
   * ```ts
   * Deno.serve((_req) => new Response("Hello, world"));
   * ```
   *
   * You can change the address to listen on using the `hostname` and `port`
   * options. The below example serves on port `3000`.
   *
   * ```ts
   * Deno.serve({ port: 3000 }, (_req) => new Response("Hello, world"));
   * ```
   *
   * You can stop the server with an {@linkcode AbortSignal}. The abort signal
   * needs to be passed as the `signal` option in the options bag. The server
   * aborts when the abort signal is aborted. To wait for the server to close,
   * await the promise returned from the `Deno.serve` API.
   *
   * ```ts
   * const ac = new AbortController();
   *
   * Deno.serve({ signal: ac.signal }, (_req) => new Response("Hello, world"))
   *  .then(() => console.log("Server closed"));
   *
   * console.log("Closing server...");
   * ac.abort();
   * ```
   *
   * By default `Deno.serve` prints the message
   * `Listening on http://<hostname>:<port>/` on listening. If you like to
   * change this behavior, you can specify a custom `onListen` callback.
   *
   * ```ts
   * Deno.serve({
   *   onListen({ port, hostname }) {
   *     console.log(`Server started at http://${hostname}:${port}`);
   *     // ... more info specific to your server ..
   *   },
   *   handler: (_req) => new Response("Hello, world"),
   * });
   * ```
   *
   * To enable TLS you must specify the `key` and `cert` options.
   *
   * ```ts
   * const cert = "-----BEGIN CERTIFICATE-----\n...\n-----END CERTIFICATE-----\n";
   * const key = "-----BEGIN PRIVATE KEY-----\n...\n-----END PRIVATE KEY-----\n";
   * Deno.serve({ cert, key }, (_req) => new Response("Hello, world"));
   * ```
   *
   * @category HTTP Server
   */
  export function serve(
    options: ServeInit & (ServeOptions | ServeTlsOptions),
  ): Promise<void>;

  /** **UNSTABLE**: New API, yet to be vetted.
   *
   * Allows "hijacking" the connection that the request is associated with. This
   * can be used to implement protocols that build on top of HTTP (eg.
   * {@linkcode WebSocket}).
   *
   * The returned promise returns underlying connection and first packet
   * received. The promise shouldn't be awaited before responding to the
   * `request`, otherwise event loop might deadlock.
   *
   * ```ts
   * function handler(req: Request): Response {
   *   Deno.upgradeHttp(req).then(([conn, firstPacket]) => {
   *     // ...
   *   });
   *   return new Response(null, { status: 101 });
   * }
   * ```
   *
   * This method can only be called on requests originating the
   * {@linkcode Deno.serveHttp} server.
   *
   * @category HTTP Server
   */
  export function upgradeHttp(
    request: Request,
  ): Promise<[Deno.Conn, Uint8Array]>;

  /** **UNSTABLE**: New API, yet to be vetted.
   *
   * Allows "hijacking" the connection that the request is associated with.
   * This can be used to implement protocols that build on top of HTTP (eg.
   * {@linkcode WebSocket}).
   *
   * Unlike {@linkcode Deno.upgradeHttp} this function does not require that you
   * respond to the request with a {@linkcode Response} object. Instead this
   * function returns the underlying connection and first packet received
   * immediately, and then the caller is responsible for writing the response to
   * the connection.
   *
   * This method can only be called on requests originating the
   * {@linkcode Deno.serve} server.
   *
   * @category HTTP Server
   */
  export function upgradeHttpRaw(request: Request): [Deno.Conn, Uint8Array];

  /** **UNSTABLE**: New API, yet to be vetted.
   *
   * Options which can be set when calling {@linkcode Deno.spawn},
   * {@linkcode Deno.spawnSync}, and {@linkcode Deno.spawnChild}.
   *
   * @category Sub Process
   */
  export interface SpawnOptions {
    /** Arguments to pass to the process. */
    args?: string[];
    /**
     * The working directory of the process.
     *
     * If not specified, the `cwd` of the parent process is used.
     */
    cwd?: string | URL;
    /**
     * Clear environmental variables from parent process.
     *
     * Doesn't guarantee that only `env` variables are present, as the OS may
     * set environmental variables for processes.
     */
    clearEnv?: boolean;
    /** Environmental variables to pass to the subprocess. */
    env?: Record<string, string>;
    /**
     * Sets the child process’s user ID. This translates to a setuid call in the
     * child process. Failure in the set uid call will cause the spawn to fail.
     */
    uid?: number;
    /** Similar to `uid`, but sets the group ID of the child process. */
    gid?: number;
    /**
     * An {@linkcode AbortSignal} that allows closing the process using the
     * corresponding {@linkcode AbortController} by sending the process a
     * SIGTERM signal.
     *
     * Not supported in {@linkcode Deno.spawnSync}.
     */
    signal?: AbortSignal;

    /** How `stdin` of the spawned process should be handled.
     *
     * Defaults to `"null"`. */
    stdin?: "piped" | "inherit" | "null";
    /**  How `stdout` of the spawned process should be handled.
     *
     * Defaults to `"piped"`. */
    stdout?: "piped" | "inherit" | "null";
    /**  How `stderr` of the spawned process should be handled.
     *
     * Defaults to "piped". */
    stderr?: "piped" | "inherit" | "null";

    /** Skips quoting and escaping of the arguments on windows. This option
     * is ignored on non-windows platforms. Defaults to `false`. */
    windowsRawArguments?: boolean;
  }

  /** **UNSTABLE**: New API, yet to be vetted.
   *
   * Spawns a child process.
   *
   * If any stdio options are not set to `"piped"`, accessing the corresponding
   * field on the `Child` or its `SpawnOutput` will throw a `TypeError`.
   *
   * If `stdin` is set to `"piped"`, the `stdin` {@linkcode WritableStream}
   * needs to be closed manually.
   *
   * ```ts
   * const child = Deno.spawnChild(Deno.execPath(), {
   *   args: [
   *     "eval",
   *     "console.log('Hello World')",
   *   ],
   *   stdin: "piped",
   * });
   *
   * // open a file and pipe the subprocess output to it.
   * child.stdout.pipeTo(Deno.openSync("output").writable);
   *
   * // manually close stdin
   * child.stdin.close();
   * const status = await child.status;
   * ```
   *
   * @category Sub Process
   */
  export function spawnChild(
    command: string | URL,
    options?: SpawnOptions,
  ): Child;

  /** **UNSTABLE**: New API, yet to be vetted.
   *
   * The interface for handling a child process returned from
   * {@linkcode Deno.spawnChild}.
   *
   * @category Sub Process
   */
  export class Child {
    get stdin(): WritableStream<Uint8Array>;
    get stdout(): ReadableStream<Uint8Array>;
    get stderr(): ReadableStream<Uint8Array>;
    readonly pid: number;
    /** Get the status of the child. */
    readonly status: Promise<ChildStatus>;

    /** Waits for the child to exit completely, returning all its output and
     * status. */
    output(): Promise<SpawnOutput>;
    /** Kills the process with given {@linkcode Deno.Signal}. Defaults to
     * `"SIGTERM"`. */
    kill(signo?: Signal): void;

    /** Ensure that the status of the child process prevents the Deno process
     * from exiting. */
    ref(): void;
    /** Ensure that the status of the child process does not block the Deno
     * process from exiting. */
    unref(): void;
  }

  /** **UNSTABLE**: New API, yet to be vetted.
   *
   * Executes a subprocess, waiting for it to finish and collecting all of its
   * output.
   *
   * Will throw an error if `stdin: "piped"` is passed.
   *
   * If options `stdout` or `stderr` are not set to `"piped"`, accessing the
   * corresponding field on `SpawnOutput` will throw a `TypeError`.
   *
   * ```ts
   * const { code, stdout, stderr } = await Deno.spawn(Deno.execPath(), {
   *   args: [
   *     "eval",
   *        "console.log('hello'); console.error('world')",
   *   ],
   * });
   * console.assert(code === 0);
   * console.assert("hello\n" === new TextDecoder().decode(stdout));
   * console.assert("world\n" === new TextDecoder().decode(stderr));
   * ```
   *
   * @category Sub Process
   */
  export function spawn(
    command: string | URL,
    options?: SpawnOptions,
  ): Promise<SpawnOutput>;

  /** **UNSTABLE**: New API, yet to be vetted.
   *
   * Synchronously executes a subprocess, waiting for it to finish and
   * collecting all of its output.
   *
   * Will throw an error if `stdin: "piped"` is passed.
   *
   * If options `stdout` or `stderr` are not set to `"piped"`, accessing the
   * corresponding field on `SpawnOutput` will throw a `TypeError`.
   *
   * ```ts
   * const { code, stdout, stderr } = Deno.spawnSync(Deno.execPath(), {
   *   args: [
   *     "eval",
   *       "console.log('hello'); console.error('world')",
   *   ],
   * });
   * console.assert(code === 0);
   * console.assert("hello\n" === new TextDecoder().decode(stdout));
   * console.assert("world\n" === new TextDecoder().decode(stderr));
   * ```
   *
   * @category Sub Process
   */
  export function spawnSync(
    command: string | URL,
    options?: SpawnOptions,
  ): SpawnOutput;

  /** **UNSTABLE**: New API, yet to be vetted.
   *
   * @category Sub Process
   */
  export interface ChildStatus {
    /** If the child process exits with a 0 status code, `success` will be set
     * to `true`, otherwise `false`. */
    success: boolean;
    /** The exit code of the child process. */
    code: number;
    /** The signal associated with the child process, present if
     * {@linkcode Deno.spawn} was called. */
    signal: Signal | null;
  }

  /** **UNSTABLE**: New API, yet to be vetted.
   *
   * The interface returned from calling {@linkcode Deno.spawn} or
   * {@linkcode Deno.spawnSync} which represents the result of spawning the
   * child process.
   *
   * @category Sub Process
   */
  export interface SpawnOutput extends ChildStatus {
    /** The buffered output from the child processes `stdout`. */
    readonly stdout: Uint8Array;
    /** The buffered output from the child processes `stderr`. */
    readonly stderr: Uint8Array;
  }
}

/** **UNSTABLE**: New API, yet to be vetted.
 *
 * The [Fetch API](https://developer.mozilla.org/en-US/docs/Web/API/Fetch_API)
 * which also supports setting a {@linkcode Deno.HttpClient} which provides a
 * way to connect via proxies and use custom TLS certificates.
 *
 * @tags allow-net, allow-read
 * @category Fetch API
 */
declare function fetch(
  input: Request | URL | string,
  init?: RequestInit & { client: Deno.HttpClient },
): Promise<Response>;

/** **UNSTABLE**: New API, yet to be vetted.
 *
 * @category Web Workers
 */
declare interface WorkerOptions {
  /** **UNSTABLE**: New API, yet to be vetted.
   *
   * Configure permissions options to change the level of access the worker will
   * have. By default it will have no permissions. Note that the permissions
   * of a worker can't be extended beyond its parent's permissions reach.
   *
   * - `"inherit"` will take the permissions of the thread the worker is created
   *   in.
   * - `"none"` will use the default behavior and have no permission
   * - A list of routes can be provided that are relative to the file the worker
   *   is created in to limit the access of the worker (read/write permissions
   *   only)
   *
   * Example:
   *
   * ```ts
   * // mod.ts
   * const worker = new Worker(
   *   new URL("deno_worker.ts", import.meta.url).href, {
   *     type: "module",
   *     deno: {
   *       permissions: {
   *         read: true,
   *       },
   *     },
   *   }
   * );
   * ```
   */
  deno?: {
    /** Set to `"none"` to disable all the permissions in the worker. */
    permissions?: Deno.PermissionOptions;
  };
}

/** **UNSTABLE**: New API, yet to be vetted.
 *
 * @category Web Sockets
 */
declare interface WebSocketStreamOptions {
  protocols?: string[];
  signal?: AbortSignal;
  headers?: HeadersInit;
}

/** **UNSTABLE**: New API, yet to be vetted.
 *
 * @category Web Sockets
 */
declare interface WebSocketConnection {
  readable: ReadableStream<string | Uint8Array>;
  writable: WritableStream<string | Uint8Array>;
  extensions: string;
  protocol: string;
}

/** **UNSTABLE**: New API, yet to be vetted.
 *
 * @category Web Sockets
 */
declare interface WebSocketCloseInfo {
  code?: number;
  reason?: string;
}

/** **UNSTABLE**: New API, yet to be vetted.
 *
 * @tags allow-net
 * @category Web Sockets
 */
declare class WebSocketStream {
  constructor(url: string, options?: WebSocketStreamOptions);
  url: string;
  connection: Promise<WebSocketConnection>;
  closed: Promise<WebSocketCloseInfo>;
  close(closeInfo?: WebSocketCloseInfo): void;
}