[NetworkRequest] make requests cancellable #46 (#56)

* only call the xhr abort if the request has been sent

* test request constructor to get at least a bit of coverage

core/NetworkRequest.js

@@ -27,6 +27,8 @@ const stripHashKey = function(object) {
     return object;
 };
 
+const xhrMap = new WeakMap();
+
 /**
  * A network request
  */
@@ -71,6 +73,9 @@ const NetworkRequest = {
      */
     completed: false,
 
+    /** @type {Promise} */
+    promise: null,
+
     /**
      * The constructor for the NetworkRequest. It simply sets up the properties.
      *
@@ -159,6 +164,8 @@ const NetworkRequest = {
     send() {
         const xhr = new XMLHttpRequest();
 
+        xhrMap.set(this, xhr);
+
         if (this.method === 'GET' && this._body) {
             this.url += `?${  Object.keys(this._body).map((key) => {
                 return `${key}=${this._body[key]}`;
@@ -211,9 +218,22 @@ const NetworkRequest = {
             xhr.send(this._body);
         }
 
+        this.promise = promise;
+
         return promise;
     },
 
+    cancel() {
+        /** @type {XMLHttpRequest} */
+        const xhr = xhrMap.get(this);
+
+        if (!xhr) {
+            return;
+        }
+
+        return xhr.abort();
+    },
+
     __proto__: EventTarget,
 };
 

tests/NetworkRequest.js

@@ -0,0 +1,21 @@
+/* eslint-env mocha */
+
+const istanbulVM = require('../testable/node/istanbulVM');
+const expect = require('chai').expect;
+
+
+describe('NetworkRequest', () => {
+    const vm = istanbulVM();
+
+    istanbulVM.applyNodeEnv(vm);
+
+    vm.runModule('../testable/core/NetworkRequest');
+
+    it('should construct a new request', () => {
+        const result = vm.runModule('./testTasks/NetworkRequest/construct');
+
+        expect(result.instance.url).to.equal('https://example.org');
+        expect(result.instance.method).to.equal('POST');
+        expect(result.instance.type).to.equal('json');
+    });
+});

tests/main.js

@@ -59,9 +59,7 @@ describe('Prototypes', () => {
     require('./EventTarget.js');
     require('./Catalog');
 
-    describe('NetworkReqest', () => {
-        Import('../../testable/core/NetworkRequest');
-    });
+    require('./NetworkRequest');
 });
 
 describe('ServiceWorker', () => {

tests/testTasks/NetworkRequest/construct.js

@@ -0,0 +1,3 @@
+/* global NetworkRequest */
+global.NetworkRequest = NetworkRequest;
+global.instance = Object.create(NetworkRequest).constructor('https://example.org', { method: 'POST', type: 'json' });