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// This is used when jstests.py runs web-platform-tests in the shell.
// Some tests require browser features that the shell doesn't have built-in.
// window.self
if (!("self" in this)) {
this.self = this;
}
// window.setTimeout, clearTimeout, setInterval, clearInterval
if (!("setTimeout" in this)) {
// Not-very-compliant polyfill for setTimeout, based on Promise.
// When this array becomes non-empty, call scheduleWork.
let timeouts = [];
// Fake clock used to order timeouts.
let now = 0;
// Least positive integer not yet used as a timer id.
let next_id = 1;
// Add an active timer record to timeouts.
function enqueue(id, t, cb) {
if (typeof cb !== 'function') {
let code = "" + cb;
cb = () => eval(code);
}
t += now;
timeouts.push({id, t, cb});
timeouts.sort((a, b) => a.t - b.t);
if (timeouts.length === 1) {
scheduleWork();
}
}
// Register a microtask to make sure timers are actually processed. There
// should be at most one of these microtasks pending at a time.
function scheduleWork() {
// Number of times to let the microtask queue spin before running a
// timeout. The idea is to let all Promises resolve between consecutive
// timer callbacks. Of course, this is a hack; whatever number is used
// here, an async function can simply await that many times plus one to
// observe that timeouts are being handled as microtasks, not events.
let delay = 10;
function handleTimeouts() {
if (--delay > 0) {
Promise.resolve().then(handleTimeouts);
return;
}
if (timeouts.length > 0) {
let {t, cb} = timeouts.shift();
if (now < t) {
now = t;
}
if (timeouts.length > 0) {
scheduleWork(); // There's more to do after this.
}
cb();
}
}
Promise.resolve().then(handleTimeouts);
}
this.setTimeout = function (cb, t, ...args) {
let id = next_id++;
enqueue(id, t, () => cb(...args));
return id;
};
this.clearTimeout = function (id) {
timeouts = timeouts.filter(obj => obj.id !== id);
};
this.setInterval = function (cb, t, ...args) {
let id = next_id++;
let func = () => {
enqueue(id, t, func);
cb(...args);
};
enqueue(id, t, func);
return id;
};
this.clearInterval = this.clearTimeout;
}
// Some tests in web platform tests leave promise rejections unhandled.
if ("ignoreUnhandledRejections" in this) {
ignoreUnhandledRejections();
}