You can not select more than 25 topics
Topics must start with a letter or number, can include dashes ('-') and can be up to 35 characters long.
120 lines
2.4 KiB
120 lines
2.4 KiB
'use strict';
|
|
|
|
var CanceledError = require('./CanceledError');
|
|
|
|
/**
|
|
* 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;
|
|
|
|
// eslint-disable-next-line func-names
|
|
this.promise.then(function(cancel) {
|
|
if (!token._listeners) return;
|
|
|
|
var i;
|
|
var l = token._listeners.length;
|
|
|
|
for (i = 0; i < l; i++) {
|
|
token._listeners[i](cancel);
|
|
}
|
|
token._listeners = null;
|
|
});
|
|
|
|
// eslint-disable-next-line func-names
|
|
this.promise.then = function(onfulfilled) {
|
|
var _resolve;
|
|
// eslint-disable-next-line func-names
|
|
var promise = new Promise(function(resolve) {
|
|
token.subscribe(resolve);
|
|
_resolve = resolve;
|
|
}).then(onfulfilled);
|
|
|
|
promise.cancel = function reject() {
|
|
token.unsubscribe(_resolve);
|
|
};
|
|
|
|
return promise;
|
|
};
|
|
|
|
executor(function cancel(message) {
|
|
if (token.reason) {
|
|
// Cancellation has already been requested
|
|
return;
|
|
}
|
|
|
|
token.reason = new CanceledError(message);
|
|
resolvePromise(token.reason);
|
|
});
|
|
}
|
|
|
|
/**
|
|
* Throws a `CanceledError` if cancellation has been requested.
|
|
*/
|
|
CancelToken.prototype.throwIfRequested = function throwIfRequested() {
|
|
if (this.reason) {
|
|
throw this.reason;
|
|
}
|
|
};
|
|
|
|
/**
|
|
* Subscribe to the cancel signal
|
|
*/
|
|
|
|
CancelToken.prototype.subscribe = function subscribe(listener) {
|
|
if (this.reason) {
|
|
listener(this.reason);
|
|
return;
|
|
}
|
|
|
|
if (this._listeners) {
|
|
this._listeners.push(listener);
|
|
} else {
|
|
this._listeners = [listener];
|
|
}
|
|
};
|
|
|
|
/**
|
|
* Unsubscribe from the cancel signal
|
|
*/
|
|
|
|
CancelToken.prototype.unsubscribe = function unsubscribe(listener) {
|
|
if (!this._listeners) {
|
|
return;
|
|
}
|
|
var index = this._listeners.indexOf(listener);
|
|
if (index !== -1) {
|
|
this._listeners.splice(index, 1);
|
|
}
|
|
};
|
|
|
|
/**
|
|
* 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;
|