78 lines
1.3 KiB
JavaScript
78 lines
1.3 KiB
JavaScript
|
'use strict';
|
||
|
|
|
||
|
|
class CancelError extends Error {
|
||
|
|
constructor() {
|
||
|
|
super('Promise was canceled');
|
||
|
|
this.name = 'CancelError';
|
||
|
|
}
|
||
|
|
}
|
||
|
|
|
||
|
|
class PCancelable {
|
||
|
|
static fn(fn) {
|
||
|
|
return function () {
|
||
|
|
const args = [].slice.apply(arguments);
|
||
|
|
return new PCancelable((onCancel, resolve, reject) => {
|
||
|
|
args.unshift(onCancel);
|
||
|
|
fn.apply(null, args).then(resolve, reject);
|
||
|
|
});
|
||
|
|
};
|
||
|
|
}
|
||
|
|
|
||
|
|
constructor(executor) {
|
||
|
|
this._pending = true;
|
||
|
|
this._canceled = false;
|
||
|
|
|
||
|
|
this._promise = new Promise((resolve, reject) => {
|
||
|
|
this._reject = reject;
|
||
|
|
|
||
|
|
return executor(
|
||
|
|
fn => {
|
||
|
|
this._cancel = fn;
|
||
|
|
},
|
||
|
|
val => {
|
||
|
|
this._pending = false;
|
||
|
|
resolve(val);
|
||
|
|
},
|
||
|
|
err => {
|
||
|
|
this._pending = false;
|
||
|
|
reject(err);
|
||
|
|
}
|
||
|
|
);
|
||
|
|
});
|
||
|
|
}
|
||
|
|
|
||
|
|
then() {
|
||
|
|
return this._promise.then.apply(this._promise, arguments);
|
||
|
|
}
|
||
|
|
|
||
|
|
catch() {
|
||
|
|
return this._promise.catch.apply(this._promise, arguments);
|
||
|
|
}
|
||
|
|
|
||
|
|
cancel() {
|
||
|
|
if (!this._pending || this._canceled) {
|
||
|
|
return;
|
||
|
|
}
|
||
|
|
|
||
|
|
if (typeof this._cancel === 'function') {
|
||
|
|
try {
|
||
|
|
this._cancel();
|
||
|
|
} catch (err) {
|
||
|
|
this._reject(err);
|
||
|
|
}
|
||
|
|
}
|
||
|
|
|
||
|
|
this._canceled = true;
|
||
|
|
this._reject(new CancelError());
|
||
|
|
}
|
||
|
|
|
||
|
|
get canceled() {
|
||
|
|
return this._canceled;
|
||
|
|
}
|
||
|
|
}
|
||
|
|
|
||
|
|
Object.setPrototypeOf(PCancelable.prototype, Promise.prototype);
|
||
|
|
|
||
|
|
module.exports = PCancelable;
|
||
|
|
module.exports.CancelError = CancelError;
|