es6-promise

This question already has an answer here: Are JavaScript forever-pending promises bad? 2 answers The problem is like this function demo() { return new Promise((resolve, reject) => { ... // The problem here!! //I just found in some rare case we failed to call resolve or reject }) } demo() .then(res => { console.log('resolve') console.log(res) }) .catch(rej => { console.log('reject') console.log(rej) }) .finally(() => { console.log('why') }) When I failed to call resolve or reject, even the finally block is not called! Why ? I had thought it was a bug then I found the original author seemed to

I have some promises and a Promise.all: array = []; var one = new Promise(function(resolve, reject) { // Do stuff setTimeout(function() { resolve('One Done'); array.push('one'); }, 5000); }); var two = new Promise(function(resolve, reject) { // Do Stuff resolve('Two Done'); array.push('two'); }); Promise.all(array).then(values => { console.log(values); }); We know this doesn't work because array.push needs to be outside. I currently have a few functions which I need to have called by promises so that finally I can have it in Promise.all. Would it be advisable to call the function from inside

my aim is to fetch data from two URLs and perform an action only when both have come back successfully. On the other hand i want to return an error if either of them fail. I have played around with my code and managed to get the desired effect. My question is, is there a more efficient, succinct way of achieving the same functionality? Helper functions let status = (r) => { if (r.ok) { return Promise.resolve(r) } else { return Promise.reject(new Error(r.statusText)) } } let json = (r) => r.json(); Requests let urls = [ 'http://localhost:3000/incomplete', 'http://localhost:3000/complete' ] let

This question already has an answer here: Using async/await with a forEach loop 15 answers Given the following code class SomeClass { async someFunc() { const urlParameters = [0, 1, 2]; const batchAjaxResult = await urlParameters.map((parameter) => { const result = await $.get(`someUrl/${parameter}`); return { parameter, result } }); console.log(batchAjaxResult); } } JavaScript will return an Array of resolved Promises instead of the actual Promises result. This is probably due to Array.map() not being implemented as a Promise. Is there a Promise-based version of Array.map ? This is question

I have a function say myMainFunction that is called from a client, that in turn calls mypromisified function. Scenario: mypromisified function can fail intermittently and I need to call this function with a delay (at an exponential increase) until success or until max no of tries reached. What I have so far The following code illustrates my scenario and repeats itself until success, but it tries indefinitely and not until certain count is reached // called once from the client myMainFuntion(); function rejectDelay(delay, reason) { // call main function at a delayed interval until success //

I want to run some asynchronous task in a loop, but it should execute in sequence order(one after another). It should be vanilla JS, not with any libraries. var doSome = function(i) { return Promise.resolve(setTimeout(() => { console.log('done... ' + i) }, 1000 * (i%3))); } var looper = function() { var p = Promise.resolve(); [1,2,3].forEach((n) => { p = p.then(() => doSome(n)) }) return p; } looper(); Current output: calling for ...1 calling for ...2 calling for ...3 Promise {<resolved>: 8260} done... 3 done... 1 done... 2 Expected output: calling for ...1 calling for ...2 calling for ...3