q | 易学教程

Using promises - Logging stack trace in fail handler

阅读更多关于 Using promises - Logging stack trace in fail handler

I am rather new to nodejs so I will explain in a bit more detail what I am trying to do. I have a webserver. If a request fails I want to log the stack trace of that exception, but deliver a error page and not crash the server. As an example, the function handling the requests: var Q = require('q'); var requestHandler = function () { // Here I get the data etc. that was requested. As this is not important, just a dummy here Q.resolve() // Now I answer the request .then(function (data) { // Dummy Code representing the sending of a response console.log('sending response …'); console.log('oh no!

Is promise.all useful given that javascript is executed in a single thread?

阅读更多关于 Is promise.all useful given that javascript is executed in a single thread?

问题 In, for example, kriskowal's Q, one can do something like: promise1.then(function(p1){ var p2 = makePromise2(); var p3 = makePromise3(); var p4 = makePromise4(); return [p2, p3, p4]; }) .all(promises, function(){ console.log('all promises fulfilled'); }, function(reason){ console.log('a promise was rejected: ' + reason.toString()); }); Given that javascript executes in a single thread, does this have any benefit, performance or otherwise, over simply doing a series of then() calls? 回答1: First

How to use “q” module for refactoring mongoose code?

阅读更多关于 How to use “q” module for refactoring mongoose code?

问题 I'm using mongoose to insert some data into mongodb. The code looks like: var mongoose = require('mongoose'); mongoose.connect('mongo://localhost/test'); var conn = mongoose.connection; // insert users conn.collection('users').insert([{/*user1*/},{/*user2*/}], function(err, docs) { var user1 = docs[0], user2 = docs[1]; // insert channels conn.collection('channels').insert([{userId:user1._id},{userId:user2._id}], function(err, docs) { var channel1 = docs[0], channel2 = docs[1]; // insert

Returning a value from a Promise

阅读更多关于 Returning a value from a Promise

问题 I would like to call the Google Maps Geocoding API using a Promise like this: function makeGeoCodingRequest(address,bounds) { /* Input parameters: address:a string bounds: an object of class google.maps.LatLngBounds(southWest,northEast) This will return a set of locations from the google geocoding library for the given query */ var url="https://maps.googleapis.com/maps/api/geocode/json?address=" + address + "&key=AIzaSyD9GBloPC20X-1kWRo7sm_0z5xvCiaSd3c"; var promise,response; var messages={

$q 'finally' not working in IE8

阅读更多关于 $q 'finally' not working in IE8

Angular 1.2 replaced always with finally on promises. So what was once this: $http.get('/myurl').always(handler); Now needs to be this: $http.get('/myurl').finally(handler); But I am getting the error "expected identifier" in IE8. How can I make this work in IE8? Found it: https://github.com/angular/angular.js/commit/f078762d48d0d5d9796dcdf2cb0241198677582c $http.get('/myurl')["finally"](handler); 来源： https://stackoverflow.com/questions/18254205/q-finally-not-working-in-ie8

q.js: difference between resolve() and fulfill()

阅读更多关于 q.js: difference between resolve() and fulfill()

I'm still unclear on the difference between calling a resolver's resolve() vs fulfill()? I see both the functions and the terms "resolve a promise" and "fulfill a promise" batted around a lot. When should I be using each? You should use resolve . deferredPromise.resolve(nextPromise) means that anything waiting for deferredPromise will now wait for nextPromise . If nextPromise is not a promise at all, it gets turned into a fulfilled promise which goes on to inform anything waiting for it that the value has become available. The fulfill method is a bad idea that will be deprecated and eventually

Returning a value from a Promise

阅读更多关于 Returning a value from a Promise

I would like to call the Google Maps Geocoding API using a Promise like this: function makeGeoCodingRequest(address,bounds) { /* Input parameters: address:a string bounds: an object of class google.maps.LatLngBounds(southWest,northEast) This will return a set of locations from the google geocoding library for the given query */ var url="https://maps.googleapis.com/maps/api/geocode/json?address=" + address + "&key=AIzaSyD9GBloPC20X-1kWRo7sm_0z5xvCiaSd3c"; var promise,response; var messages={ "ZERO_RESULTS":"No results were found", "OVER_QUERY_LIMIT":"We are over the query limit.Wait awhile

Multiple chained deferred functions using q in AngularJS stop returning data

阅读更多关于 Multiple chained deferred functions using q in AngularJS stop returning data

问题 I am trying to chain together multiple deferred function calls such that the next call gets the results of the previous deferred.resolve. When I chain together more than 2 of these calls, the data stops being returned. Here is the basic code inside an angular controller: $scope.runAsync = function() { var asyncFn1 = function(data){ var deferred = $q.defer(); $timeout(function(){ console.log("Async fn1 " + data); $scope.outputLines.push("Async fn1 " + data); deferred.resolve("Async fn1 " +

How does Angular $q.when work?

阅读更多关于 How does Angular $q.when work?

问题 Can some one explain me how does $q.when work in AngularJS? I'm trying to analyse how $http work and found this: var promise = $q.when(config); And here is config object from Chrome console: Object {transformRequest: Array[1], transformResponse: Array[1], cache: Object, method: "GET", url: "/schedule/month_index.html"…} cache: Object headers: Object method: "GET" transformRequest: Array[1] transformResponse: Array[1] url: "/schedule/month_index.html" __proto__: Object What happens next? How

Mongoose and promises: how to get an array of query results?

阅读更多关于 Mongoose and promises: how to get an array of query results?

Using mongoose to query results from the db and Q for promises, but finding it hard to wrap my head around just getting a list of users that's available. Currently I have some something like this: var checkForPerson = function( person ) { people = mongoose.model('Person', Person) return people.findOne({"_id": person }, function(err, doc) { if (err) console.log(err) if (doc !== null) { return doc } else { console.log('no results') } }) } var promises = someArrayOfIds.map(checkForPerson); // this is where I would like to have an array of models var users = Q.all(promises) //this fires off before