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denoland-deno/js/util.ts

153 lines
3.9 KiB
TypeScript

// Copyright 2018 the Deno authors. All rights reserved. MIT license.
import { TypedArray } from "./types";
let logDebug = false;
// @internal
export function setLogDebug(debug: boolean): void {
logDebug = debug;
}
/** Debug logging for deno.
* Enable with the `--log-debug` or `-D` command line flag.
* @internal
*/
// tslint:disable-next-line:no-any
export function log(...args: any[]): void {
if (logDebug) {
console.log("DEBUG JS -", ...args);
}
}
// @internal
export function assert(cond: boolean, msg = "assert") {
if (!cond) {
throw Error(msg);
}
}
// @internal
export function typedArrayToArrayBuffer(ta: TypedArray): ArrayBuffer {
const ab = ta.buffer.slice(ta.byteOffset, ta.byteOffset + ta.byteLength);
return ab as ArrayBuffer;
}
// @internal
export function arrayToStr(ui8: Uint8Array): string {
return String.fromCharCode(...ui8);
}
/** 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 interface ResolvableMethods<T> {
resolve: (value?: T | PromiseLike<T>) => void;
// tslint:disable-next-line:no-any
reject: (reason?: any) => void;
}
// @internal
export type Resolvable<T> = Promise<T> & ResolvableMethods<T>;
// @internal
export function createResolvable<T>(): Resolvable<T> {
let methods: ResolvableMethods<T>;
const promise = new Promise<T>((resolve, reject) => {
methods = { resolve, reject };
});
// TypeScript doesn't know that the Promise callback occurs synchronously
// therefore use of not null assertion (`!`)
return Object.assign(promise, methods!) as Resolvable<T>;
}
// @internal
export function notImplemented(): never {
throw new Error("Not implemented");
}
// @internal
export function unreachable(): never {
throw new Error("Code not reachable");
}
// @internal
export function hexdump(u8: Uint8Array): string {
return Array.prototype.map
.call(u8, (x: number) => {
return ("00" + x.toString(16)).slice(-2);
})
.join(" ");
}
// @internal
export function containsOnlyASCII(str: string): boolean {
if (typeof str !== "string") {
return false;
}
return /^[\x00-\x7F]*$/.test(str);
}
export interface Deferred {
promise: Promise<void>;
resolve: Function;
reject: Function;
}
/** Create a wrapper around a promise that could be resolved externally.
* TODO Do not expose this from "deno" namespace.
*/
export function deferred(): Deferred {
let resolve: Function | undefined;
let reject: Function | undefined;
const promise = new Promise<void>((res, rej) => {
resolve = res;
reject = rej;
});
return {
promise,
resolve: resolve!,
reject: reject!
};
}
// tslint:disable-next-line:variable-name
const TypedArrayConstructor = Object.getPrototypeOf(Uint8Array);
export function isTypedArray(x: unknown): x is TypedArray {
return x instanceof TypedArrayConstructor;
}
// Returns whether o is an object, not null, and not a function.
// @internal
export function isObject(o: unknown): o is object {
return o != null && typeof o === "object";
}
// @internal
export function requiredArguments(
name: string,
length: number,
required: number
): void {
if (length < required) {
const errMsg = `${name} requires at least ${required} argument${
required === 1 ? "" : "s"
}, but only ${length} present`;
throw new TypeError(errMsg);
}
}