Since you make sure to put your instances.add(this) at the end of the constructor you should IMHO be safe to tell the compiler to simply suppress the warning (*). A warning, by its nature, doesn’t necessarily mean that there’s something wrong, it just requires your attention. If you know what you’re doing you can use … Read more
For preserving the context, the bind method is really useful, it’s now part of the recently released ECMAScript 5th Edition Specification, the implementation of this function is simple (only 8 lines long): // The .bind method from Prototype.js if (!Function.prototype.bind) { // check if native implementation available Function.prototype.bind = function(){ var fn = this, args … Read more
This is the correct way public static function userNameAvailibility() { $result = self::getsomthin(); } Use self:: instead of $this-> for static methods. See: PHP Static Methods Tutorial for more info 🙂
$(this).siblings().hide(); Traversing/Siblings
Value of this in a node module: this in NodeJS global scope is the current module.exports object, not the global object. This is different from a browser where the global scope is the global window object. Consider the following code executed in Node: console.log(this); // logs {} module.exports.foo = 5; console.log(this); // log { foo:5 … Read more
If you want this captured the TypeScript way of doing this is via arrow functions. To quote Anders: The this in arrow functions is lexically scoped Here is the way I like to use this to my advantage: class test{ // Use arrow functions func1=(arg:string)=>{ return arg+” yeah” + this.prop; } func2=(arg:number)=>{ return arg+10 + … Read more
Array.prototype.map() takes a second argument to set what this refers to in the mapping function, so pass this as the second argument to preserve the current context: someList.map(function(item) { … }, this) Alternatively, you can use an ES6 arrow function to automatically preserve the current this context: someList.map((item) => { … })
You have a few options here, each with its own trade-offs. Unfortunately there is no obvious best solution and it will really depend on the application. Automatic Class Binding As shown in your question: class DemonstrateScopingProblems { private status = “blah”; public run = () => { alert(this.status); } } Good/bad: This creates an additional … Read more
No it can’t. If you’re using this, then you’re in the instance so this isn’t null. The JLS says : When used as a primary expression, the keyword this denotes a value that is a reference to the object for which the instance method was invoked (§15.12), or to the object being constructed. If you … Read more
In JavaScript the this object is really based on how you make your function calls. In general there are three ways to setup the this object: someThing.someFunction(arg1, arg2, argN) someFunction.call(someThing, arg1, arg2, argN) someFunction.apply(someThing, [arg1, arg2, argN]) In all of the above examples the this object will be someThing. Calling a function without a leading … Read more