Linked Questions
2,756 questions linked to/from How to access the correct `this` inside a callback
243
votes
19
answers
89k
views
Unable to access React instance (this) inside event handler [duplicate]
I am writing a simple component in ES6 (with BabelJS), and functions this.setState is not working.
Typical errors include something like
Cannot read property 'setState' of undefined
or
this....
- 3,409
185
votes
1
answer
432k
views
Angular 2 - Using 'this' inside setTimeout [duplicate]
I have a function like so in my class
showMessageSuccess(){
var that = this;
this.messageSuccess = true;
setTimeout(function(){
that.messageSuccess = false;
},3000);
}
...
- 4,212
93
votes
7
answers
73k
views
Preserving a reference to "this" in JavaScript prototype functions [duplicate]
I'm just getting into using prototypal JavaScript and I'm having trouble figuring out how to preserve a this reference to the main object from inside a prototype function when the scope changes. Let ...
- 36.6k
58
votes
7
answers
55k
views
JavaScript Callback Scope [duplicate]
I'm having some trouble with plain old JavaScript (no frameworks) in referencing my object in a callback function.
function foo(id) {
this.dom = document.getElementById(id);
this.bar = 5;
...
- 6,106
48
votes
8
answers
47k
views
'this' in function inside prototype function [duplicate]
I basically have an object, extended with a function through its prototype. Inside that function, another function exists, however when using this in this nested function, it does not seem to refer to ...
- 154k
43
votes
4
answers
46k
views
Variable inside setTimeout says it is undefined, but when outside it is defined [duplicate]
I have a class. I need to do some http work inside of a timeout. The problem I am faceing is the http variable inside the timeout keeps saying it is undefined.
export class MyClass {
http:Http:
...
- 6,172
51
votes
1
answer
53k
views
ES6 Class: access to 'this' with 'addEventListener' applied on method [duplicate]
In this es6 script, the click event don't works because sayHello method is called with this.elm (<div>) as this.
how to associate a event to a method without loose the scope?
class player{
...
- 16.7k
34
votes
1
answer
49k
views
React. this.setState is not a function inside setTimeout [duplicate]
Current component has state.breaker value of false. When the scroll event is captured it looks at the state and if its false it does some stuff.
I would like to have some kind of static delay before ...
- 2,562
45
votes
2
answers
37k
views
Referencing "this" inside setInterval/setTimeout within object prototype methods [duplicate]
Normally I'd assign an alternative "self" reference when referring to "this" within setInterval. Is it possible to accomplish something similar within the context of a prototype method? The following ...
- 507
30
votes
3
answers
29k
views
Calling a class prototype method by a setInterval event [duplicate]
I have a simple javascript class.
One method of this class sets up a timer using setInterval function. The method that I want to call every time the event fires is defined inside the same class.
...
- 3,404
20
votes
1
answer
49k
views
this.setState is not a function [duplicate]
I have the following component, which maintains the state that gets updated when the event is fired on the an specific element and when the state is updated it is passed down as a prop to another ...
- 2,763
47
votes
1
answer
38k
views
"This" within es6 class method [duplicate]
For some reason I'm getting weird values for "this" in my es6 class...
'use strict';
class Clicker {
constructor(element) {
this.count = 0;
this.elem = element;
this.elem....
- 1,844
15
votes
7
answers
15k
views
How to pass "this" to window setInterval [duplicate]
Suppose I have a function a:
function a() {
this.b = 1;
this.set = setInterval(function() {console.log(this.b);}, 200);
}
So when a.set() is called the anonymous function will be called. ...
- 2,519
27
votes
4
answers
5k
views
Why doesn't ["A","B","C"].map(String.prototype.toLowerCase.call) work? [duplicate]
This, of course, returns what you would expect:
["A","B","C"].map(function (x) {
return x.toLowerCase();
});
// --> ["a", "b", "c"]
So does using String.prototype.toLowerCase.call:
["A","B","...
- 299
26
votes
1
answer
25k
views
How to access 'this' inside a callback function in Typescript? [duplicate]
I am trying to set a variable declared at the beginning of the class (a boolean) to true once a callback is called, but I keep getting a TypeScript erorr.
Here is the error:
TypeError: Cannot set ...
- 613