EDIT: In summary, back in 2010 when this question was asked the most common way to solve this problem was to save a reference to the context where the setTimeout function call is made, because setTimeout executes the function with this pointing to the global object: var that = this; if (this.options.destroyOnHide) { setTimeout(function(){ that.tip.destroy() … Read more
setTimeout(function() { postinsql(topicId); }, 4000) You need to feed an anonymous function as a parameter instead of a string, the latter method shouldn’t even work per the ECMAScript specification but browsers are just lenient. This is the proper solution, don’t ever rely on passing a string as a ‘function’ when using setTimeout() or setInterval(), it’s … Read more
An Objective-C delegate is an object that has been assigned to the delegate property another object. To create one, you define a class that implements the delegate methods you’re interested in, and mark that class as implementing the delegate protocol. For example, suppose you have a UIWebView. If you’d like to implement its delegate’s webViewDidStartLoad: … Read more
Promises are not callbacks. A promise represents the future result of an asynchronous operation. Of course, writing them the way you do, you get little benefit. But if you write them the way they are meant to be used, you can write asynchronous code in a way that resembles synchronous code and is much more … Read more
This is impossible as you cannot return from an asynchronous call inside a synchronous method. In this case you need to pass a callback to foo that will receive the return value function foo(address, fn){ geocoder.geocode( { ‘address’: address}, function(results, status) { fn(results[0].geometry.location); }); } foo(“address”, function(location){ alert(location); // this is where you get the … Read more
Promises have state, they start as pending and can settle to: fulfilled meaning that the computation completed successfully. rejected meaning that the computation failed. Promise returning functions should never throw, they should return rejections instead. Throwing from a promise returning function will force you to use both a } catch { and a .catch. People … Read more
What you should know about this this (aka “the context”) is a special keyword inside each function and its value only depends on how the function was called, not how/when/where it was defined. It is not affected by lexical scopes like other variables (except for arrow functions, see below). Here are some examples: function foo() … Read more
There’s little use in PHP for callbacks which will be called when an action has completed, e.g.: string(‘Ahmar’, function ($name) { echo … }) This is very idiomatic in languages like Javascript; but that is because Javascript has a rather different mode of execution than PHP does. In Javascript many things are usually happening at … Read more