denoland-deno/cli/js/util.ts

// Copyright 2018-2020 the Deno authors. All rights reserved. MIT license.
import { TypedArray } from "./types.ts";

let logDebug = false;
let logSource = "JS";

// @internal
export function setLogDebug(debug: boolean, source?: string): void {
  logDebug = debug;
  if (source) {
    logSource = source;
  }
}

/** Debug logging for deno.
 * Enable with the `--log-debug` or `-D` command line flag.
 * @internal
 */
export function log(...args: unknown[]): void {
  if (logDebug) {
    // if we destructure `console` off `globalThis` too early, we don't bind to
    // the right console, therefore we don't log anything out.
    globalThis.console.log(`DEBUG ${logSource} -`, ...args);
  }
}

// @internal
export function assert(cond: unknown, msg = "assert"): asserts cond {
  if (!cond) {
    throw Error(msg);
  }
}

/** A `Resolvable` is a Promise with the `reject` and `resolve` functions
 * placed as methods on the promise object itself. It allows you to do:
 *
 *       const p = createResolvable<number>();
 *       // ...
 *       p.resolve(42);
 *
 * It'd be prettier to make `Resolvable` a class that inherits from `Promise`,
 * rather than an interface. This is possible in ES2016, however typescript
 * produces broken code when targeting ES5 code.
 *
 * At the time of writing, the GitHub issue is closed in favour of a proposed
 * solution that is awaiting feedback.
 *
 * @see https://github.com/Microsoft/TypeScript/issues/15202
 * @see https://github.com/Microsoft/TypeScript/issues/15397
 * @internal
 */

export type ResolveFunction<T> = (value?: T | PromiseLike<T>) => void;
// eslint-disable-next-line @typescript-eslint/no-explicit-any
export type RejectFunction = (reason?: any) => void;

export interface ResolvableMethods<T> {
  resolve: ResolveFunction<T>;
  reject: RejectFunction;
}

// @internal
export type Resolvable<T> = Promise<T> & ResolvableMethods<T>;

// @internal
export function createResolvable<T>(): Resolvable<T> {
  let resolve: ResolveFunction<T>;
  let reject: RejectFunction;
  const promise = new Promise<T>((res, rej): void => {
    resolve = res;
    reject = rej;
  }) as Resolvable<T>;
  promise.resolve = resolve!;
  promise.reject = reject!;
  return promise;
}

// @internal
export function notImplemented(): never {
  throw new Error("Not implemented");
}

// @internal
export function unreachable(): never {
  throw new Error("Code not reachable");
}

const TypedArrayConstructor = Object.getPrototypeOf(Uint8Array);
export function isTypedArray(x: unknown): x is TypedArray {
  return x instanceof TypedArrayConstructor;
}

// @internal
export function requiredArguments(
  name: string,
  length: number,
  required: number
): void {
  if (length < required) {
    const errMsg = `${name} requires at least ${required} argument${
      required === 1 ? "" : "s"
    }, but only ${length} present`;
    throw new TypeError(errMsg);
  }
}

// @internal
export function immutableDefine(
  // eslint-disable-next-line @typescript-eslint/no-explicit-any
  o: any,
  p: string | number | symbol,
  // eslint-disable-next-line @typescript-eslint/no-explicit-any
  value: any
): void {
  Object.defineProperty(o, p, {
    value,
    configurable: false,
    writable: false
  });
}

// Returns values from a WeakMap to emulate private properties in JavaScript
export function getPrivateValue<
  K extends object,
  V extends object,
  W extends keyof V
>(instance: K, weakMap: WeakMap<K, V>, key: W): V[W] {
  if (weakMap.has(instance)) {
    return weakMap.get(instance)![key];
  }
  throw new TypeError("Illegal invocation");
}

/**
 * Determines whether an object has a property with the specified name.
 * Avoid calling prototype builtin `hasOwnProperty` for two reasons:
 *
 * 1. `hasOwnProperty` is defined on the object as something else:
 *
 *      const options = {
 *        ending: 'utf8',
 *        hasOwnProperty: 'foo'
 *      };
 *      options.hasOwnProperty('ending') // throws a TypeError
 *
 * 2. The object doesn't inherit from `Object.prototype`:
 *
 *       const options = Object.create(null);
 *       options.ending = 'utf8';
 *       options.hasOwnProperty('ending'); // throws a TypeError
 *
 * @param obj A Object.
 * @param v A property name.
 * @see https://eslint.org/docs/rules/no-prototype-builtins
 * @internal
 */
export function hasOwnProperty<T>(obj: T, v: PropertyKey): boolean {
  if (obj == null) {
    return false;
  }
  return Object.prototype.hasOwnProperty.call(obj, v);
}