57 lines
1.2 KiB
JavaScript
57 lines
1.2 KiB
JavaScript
'use strict';
|
|
|
|
var Cancel = require('./Cancel');
|
|
|
|
/**
|
|
* A `CancelToken` is an object that can be used to request cancellation of an operation.
|
|
*
|
|
* @class
|
|
* @param {Function} executor The executor function.
|
|
*/
|
|
function CancelToken(executor) {
|
|
if (typeof executor !== 'function') {
|
|
throw new TypeError('executor must be a function.');
|
|
}
|
|
|
|
var resolvePromise;
|
|
this.promise = new Promise(function promiseExecutor(resolve) {
|
|
resolvePromise = resolve;
|
|
});
|
|
|
|
var token = this;
|
|
executor(function cancel(message) {
|
|
if (token.reason) {
|
|
// Cancellation has already been requested
|
|
return;
|
|
}
|
|
|
|
token.reason = new Cancel(message);
|
|
resolvePromise(token.reason);
|
|
});
|
|
}
|
|
|
|
/**
|
|
* Throws a `Cancel` if cancellation has been requested.
|
|
*/
|
|
CancelToken.prototype.throwIfRequested = function throwIfRequested() {
|
|
if (this.reason) {
|
|
throw this.reason;
|
|
}
|
|
};
|
|
|
|
/**
|
|
* Returns an object that contains a new `CancelToken` and a function that, when called,
|
|
* cancels the `CancelToken`.
|
|
*/
|
|
CancelToken.source = function source() {
|
|
var cancel;
|
|
var token = new CancelToken(function executor(c) {
|
|
cancel = c;
|
|
});
|
|
return {
|
|
token: token,
|
|
cancel: cancel
|
|
};
|
|
};
|
|
|
|
module.exports = CancelToken;
|