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denoland-deno/op_crates/web/02_abort_signal.js

97 lines
2.2 KiB
JavaScript

// Copyright 2018-2020 the Deno authors. All rights reserved. MIT license.
((window) => {
const add = Symbol("add");
const signalAbort = Symbol("signalAbort");
const remove = Symbol("remove");
const illegalConstructorKey = Symbol("illegalConstructorKey");
class AbortSignal extends EventTarget {
#aborted = false;
#abortAlgorithms = new Set();
[add](algorithm) {
this.#abortAlgorithms.add(algorithm);
}
[signalAbort]() {
if (this.#aborted) {
return;
}
this.#aborted = true;
for (const algorithm of this.#abortAlgorithms) {
algorithm();
}
this.#abortAlgorithms.clear();
this.dispatchEvent(new Event("abort"));
}
[remove](algorithm) {
this.#abortAlgorithms.delete(algorithm);
}
constructor(key) {
if (key != illegalConstructorKey) {
throw new TypeError("Illegal constructor.");
}
super();
}
get aborted() {
return Boolean(this.#aborted);
}
get [Symbol.toStringTag]() {
return "AbortSignal";
}
}
defineEventHandler(AbortSignal.prototype, "abort");
class AbortController {
#signal = new AbortSignal(illegalConstructorKey);
get signal() {
return this.#signal;
}
abort() {
this.#signal[signalAbort]();
}
get [Symbol.toStringTag]() {
return "AbortController";
}
}
const handlerSymbol = Symbol("eventHandlers");
function defineEventHandler(emitter, name) {
// HTML specification section 8.1.5.1
Object.defineProperty(emitter, `on${name}`, {
get() {
return this[handlerSymbol]?.get(name);
},
set(value) {
const oldListener = this[handlerSymbol]?.get(name);
if (oldListener) {
this.removeEventListener(name, oldListener);
}
if (!this[handlerSymbol]) {
this[handlerSymbol] = new Map();
}
this.addEventListener(name, value);
this[handlerSymbol].set(value);
},
configurable: true,
enumerable: true,
});
}
window.AbortSignal = AbortSignal;
window.AbortController = AbortController;
window.__bootstrap = window.__bootstrap || {};
window.__bootstrap.abortSignal = {
add,
signalAbort,
remove,
};
})(this);