abortcontroller-polyfill
Version:
Polyfill/ponyfill for the AbortController DOM API + optional patching of fetch (stub that calls catch, doesn't actually abort request).
321 lines (275 loc) • 9.74 kB
JavaScript
(function (global, factory) {
typeof exports === 'object' && typeof module !== 'undefined' ? factory() :
typeof define === 'function' && define.amd ? define(factory) :
(factory());
}(this, (function () { 'use strict';
var classCallCheck = function (instance, Constructor) {
if (!(instance instanceof Constructor)) {
throw new TypeError("Cannot call a class as a function");
}
};
var createClass = function () {
function defineProperties(target, props) {
for (var i = 0; i < props.length; i++) {
var descriptor = props[i];
descriptor.enumerable = descriptor.enumerable || false;
descriptor.configurable = true;
if ("value" in descriptor) descriptor.writable = true;
Object.defineProperty(target, descriptor.key, descriptor);
}
}
return function (Constructor, protoProps, staticProps) {
if (protoProps) defineProperties(Constructor.prototype, protoProps);
if (staticProps) defineProperties(Constructor, staticProps);
return Constructor;
};
}();
var get = function get(object, property, receiver) {
if (object === null) object = Function.prototype;
var desc = Object.getOwnPropertyDescriptor(object, property);
if (desc === undefined) {
var parent = Object.getPrototypeOf(object);
if (parent === null) {
return undefined;
} else {
return get(parent, property, receiver);
}
} else if ("value" in desc) {
return desc.value;
} else {
var getter = desc.get;
if (getter === undefined) {
return undefined;
}
return getter.call(receiver);
}
};
var inherits = function (subClass, superClass) {
if (typeof superClass !== "function" && superClass !== null) {
throw new TypeError("Super expression must either be null or a function, not " + typeof superClass);
}
subClass.prototype = Object.create(superClass && superClass.prototype, {
constructor: {
value: subClass,
enumerable: false,
writable: true,
configurable: true
}
});
if (superClass) Object.setPrototypeOf ? Object.setPrototypeOf(subClass, superClass) : subClass.__proto__ = superClass;
};
var possibleConstructorReturn = function (self, call) {
if (!self) {
throw new ReferenceError("this hasn't been initialised - super() hasn't been called");
}
return call && (typeof call === "object" || typeof call === "function") ? call : self;
};
var Emitter = function () {
function Emitter() {
classCallCheck(this, Emitter);
this.listeners = {};
}
createClass(Emitter, [{
key: 'addEventListener',
value: function addEventListener(type, callback) {
if (!(type in this.listeners)) {
this.listeners[type] = [];
}
this.listeners[type].push(callback);
}
}, {
key: 'removeEventListener',
value: function removeEventListener(type, callback) {
if (!(type in this.listeners)) {
return;
}
var stack = this.listeners[type];
for (var i = 0, l = stack.length; i < l; i++) {
if (stack[i] === callback) {
stack.splice(i, 1);
return;
}
}
}
}, {
key: 'dispatchEvent',
value: function dispatchEvent(event) {
var _this = this;
if (!(event.type in this.listeners)) {
return;
}
var debounce = function debounce(callback) {
setTimeout(function () {
return callback.call(_this, event);
});
};
var stack = this.listeners[event.type];
for (var i = 0, l = stack.length; i < l; i++) {
debounce(stack[i]);
}
return !event.defaultPrevented;
}
}]);
return Emitter;
}();
var AbortSignal = function (_Emitter) {
inherits(AbortSignal, _Emitter);
function AbortSignal() {
classCallCheck(this, AbortSignal);
var _this2 = possibleConstructorReturn(this, (AbortSignal.__proto__ || Object.getPrototypeOf(AbortSignal)).call(this));
_this2.aborted = false;
_this2.onabort = null;
return _this2;
}
createClass(AbortSignal, [{
key: 'toString',
value: function toString() {
return '[object AbortSignal]';
}
}, {
key: 'dispatchEvent',
value: function dispatchEvent(event) {
if (event.type === 'abort') {
this.aborted = true;
if (typeof this.onabort === 'function') {
this.onabort.call(this, event);
}
}
get(AbortSignal.prototype.__proto__ || Object.getPrototypeOf(AbortSignal.prototype), 'dispatchEvent', this).call(this, event);
}
}]);
return AbortSignal;
}(Emitter);
var AbortController = function () {
function AbortController() {
classCallCheck(this, AbortController);
this.signal = new AbortSignal();
}
createClass(AbortController, [{
key: 'abort',
value: function abort() {
var event = void 0;
try {
event = new Event('abort');
} catch (e) {
if (typeof document !== 'undefined') {
// For Internet Explorer 11:
event = document.createEvent('Event');
event.initEvent('abort', false, false);
} else {
// Fallback where document isn't available:
event = {
type: 'abort',
bubbles: false,
cancelable: false
};
}
}
this.signal.dispatchEvent(event);
}
}, {
key: 'toString',
value: function toString() {
return '[object AbortController]';
}
}]);
return AbortController;
}();
if (typeof Symbol !== 'undefined' && Symbol.toStringTag) {
// These are necessary to make sure that we get correct output for:
// Object.prototype.toString.call(new AbortController())
AbortController.prototype[Symbol.toStringTag] = 'AbortController';
AbortSignal.prototype[Symbol.toStringTag] = 'AbortSignal';
}
/**
* Note: the "fetch.Request" default value is available for fetch imported from
* the "node-fetch" package and not in browsers. This is OK since browsers
* will be importing umd-polyfill.js from that path "self" is passed the
* decorator so the default value will not be used (because browsers that define
* fetch also has Request). One quirky setup where self.fetch exists but
* self.Request does not is when the "unfetch" minimal fetch polyfill is used
* on top of IE11; for this case the browser will try to use the fetch.Request
* default value which in turn will be undefined but then then "if (Request)"
* will ensure that you get a patched fetch but still no Request (as expected).
* @param {fetch, Request = fetch.Request}
* @returns {fetch: abortableFetch, Request: AbortableRequest}
*/
function abortableFetchDecorator(patchTargets) {
if ('function' === typeof patchTargets) {
patchTargets = { fetch: patchTargets };
}
var _patchTargets = patchTargets,
fetch = _patchTargets.fetch,
_patchTargets$Request = _patchTargets.Request,
NativeRequest = _patchTargets$Request === undefined ? fetch.Request : _patchTargets$Request,
_patchTargets$AbortCo = _patchTargets.AbortController,
NativeAbortController = _patchTargets$AbortCo === undefined ? AbortController : _patchTargets$AbortCo;
var Request = NativeRequest;
// Note that the "unfetch" minimal fetch polyfill defines fetch() without
// defining window.Request, and this polyfill need to work on top of unfetch
// so the below feature detection is wrapped in if (Request)
if (Request) {
// Do feature detecting
var controller = new NativeAbortController();
var signal = controller.signal;
var request = new Request('/', { signal: signal });
// Browser already supports abortable fetch (like FF v57 and fetch-polyfill)
if (request.signal) {
return { fetch: fetch, Request: Request };
}
Request = function Request(input, init) {
var request = new NativeRequest(input, init);
if (init && init.signal) {
request.signal = init.signal;
}
return request;
};
Request.prototype = NativeRequest.prototype;
}
var realFetch = fetch;
var abortableFetch = function abortableFetch(input, init) {
var signal = Request && Request.prototype.isPrototypeOf(input) ? input.signal : init ? init.signal : undefined;
if (signal) {
var abortError = void 0;
try {
abortError = new DOMException('Aborted', 'AbortError');
} catch (err) {
// IE 11 does not support calling the DOMException constructor, use a
// regular error object on it instead.
abortError = new Error('Aborted');
abortError.name = 'AbortError';
}
// Return early if already aborted, thus avoiding making an HTTP request
if (signal.aborted) {
return Promise.reject(abortError);
}
// Turn an event into a promise, reject it once `abort` is dispatched
var cancellation = new Promise(function (_, reject) {
signal.addEventListener('abort', function () {
return reject(abortError);
}, { once: true });
});
// Return the fastest promise (don't need to wait for request to finish)
return Promise.race([cancellation, realFetch(input, init)]);
}
return realFetch(input, init);
};
return { fetch: abortableFetch, Request: Request };
}
(function (self) {
if (self.AbortController) {
return;
}
self.AbortController = AbortController;
self.AbortSignal = AbortSignal;
if (!self.fetch) {
console.warn('fetch() is not available, cannot install abortcontroller-polyfill');
return;
}
var _abortableFetch = abortableFetchDecorator(self),
fetch = _abortableFetch.fetch,
Request = _abortableFetch.Request;
self.fetch = fetch;
self.Request = Request;
})(typeof self !== 'undefined' ? self : global);
})));