es6-promise

问题 I'm new to OOP. My knowledge of promises/asynchronously/synchronously running functions is simply basic. I'd really appreciate your time and attention! This is the example from React-Native docs: async function getMoviesFromApi() { try { let response = await fetch('https://facebook.github.io/react-native/movies.json'); let responseJson = await response.json(); return responseJson.movies; } catch(error) { console.error(error); } } As i understand from code above, getMoviesFromApi is declared

问题 When using supertest for testing async HTTP requests in JavaScript, what's the difference between these two snippets? Is one of them correct and the other one wrong? request('http://localhost:8080/').get('/api/people') .expect(res => res.body.should.have.length(5)) vs. request('http://localhost:8080/').get('/api/people') .then(res => res.body.should.have.length(5)) The only differences I could notice were: expect returns a Test object and, when test fails, prints a large stack trace then

问题 Is there a way to cancel a ES7 async function? In this example, on click, I want to abort async function call before calling new. async function draw(){ for(;;){ drawRandomRectOnCanvas(); await sleep(100); } } function sleep(t){ return new Promise(cb=>setTimeout(cb,t)); } let asyncCall; window.addEventListener('click', function(){ if(asyncCall) asyncCall.abort(); // this dont works clearCanvas(); asyncCall = draw(); }); 回答1: There's nothing built in to JavaScript yet, but you could easily

问题 This question already has answers here : Resolve promises one after another (i.e. in sequence)? (24 answers) Closed 4 years ago . I need to send a series of PUT & POST requests from a Service Worker. The order in which they're sent matters. Requirements: Given a request method, url, and JSON body, send the request If it succeeds ( response.status < 300 ): Pass body to a success function Call next request in queue If it fails: Pass responseText or err to error function Stop execution If I

问题 Trying to understand the order of execution of ES6 promises, I noticed the order of execution of chained handlers is affected by whether the previous handler returned a value or a promise. Example let a = Promise.resolve(); a.then(v => Promise.resolve("A")).then(v => console.log(v)); a.then(v => "B").then(v => console.log(v)); Output when run directly in Chrome (v 61) console: B A However, when clicking the Run code snippet button, I will get the order A B instead. Is the execution order

问题 I am requesting weather data from openweather API and I get "error SyntaxError: Unexpected end of JSON input at Object.parse ()" every time my promise is resolved and I do JSON.pase(daat) The JSON I get looks like this: { "coord":{"lon":24.94,"lat":60.17}, "weather":[{"id":741,"main":"Fog","description":"fog","icon":"50n"}], "base":"stations", "main":{"temp":273.15,"pressure":994,"humidity":94,"temp_min":273.15,"temp_max":273.15}, "visibility":500, "wind":{"speed":1.5}, "clouds":{"all":90},

问题 I would like to receive some help on the following code: fillDataAssociationsArray(DataAssociationIDS: string[]) { const promise = new Promise((resolve, reject) => { for (const id of DataAssociationIDS) { this.api.getDataAssociationByID(id).toPromise().then( data => { this.DataAssociations.push(data.body.entities.DATAASSOCIATIONS[0]); }); } resolve(); }); return promise;} In the code above I am trying to convert an array of DataAssociationIDS to DataAssociation objects, and than pushing them

问题 I have several async functions running. I want to wait for them all to finish before taking the next steps. Here's my code that I'm using to get all of the key/values from chrome.storage and the Promise.all() implementation. var promise1 = Promise.resolve(3); var promise2 = 42; var promise3 = new Promise(function(resolve, reject) { setTimeout(resolve, 100, 'foo'); }); var getAll = chrome.storage.sync.get(function(result) { console.log(result) }); Promise.all([promise1, promise2, promise3,

问题 I have an ES6 / Aurelia app that I am using jasmine to test. The method I am trying to test looks something like this: update() { let vm = this; vm.getData() .then((response) => { vm.processData(response); }); } Where this.getData is a function that returns a promise. My spec file looks something like this: describe('my service update function', () => { it('it will call the other functions', () => { myService = new MyService(); spyOn(myService, 'getData').and.callFake(function() { return new

问题 I am working on a promise chain that was inspired by this answer: https://stackoverflow.com/a/44955506/7485805 I want to break this for loop in order to properly handle the rejection of the chain. I just figured that I can't use break inside the .catch method of the chain. Here's my code if it helps: function pro (arr) { let chain = Promise.resolve(); const self = {req: {}, res: {}}; const length = arr.length; return new Promise((resolve, reject) => { for(let i=0; i<length; i++){ chain =