How do I get a set "this" to a variable in a component in angular2 typescript?

Question

I have a component. Inside I have the following:

constructor() {
  this.something = "Hello";
}

document.addEventListener('click', doSomething());

function doSomething(e) {
   console.log(this.something) // this is undefined
}

I want to make it so that I can access this.something inside of the doSomething(e). Usually I would just create a variable outside and use var self = this; then reference self.something to get to that "Hello". Unfortunately in angular 2, I am getting errors with self not being defined, etc. How can I access this.something inside of the event listener I created?

And where's that doSomething defined? Please, provide the context for the code you're posting. The snippet above will throw syntax error. Because constructor is outside of a class. — Estus Flask
– Estus Flask, Commented Apr 7, 2017 at 21:00

Roman Kolesnikov · Accepted Answer · 2017-04-07 20:14:06Z

1

You should use lambda function to get correct this

document.addEventListener('click', () => doSomething());

answered Apr 7, 2017 at 20:14

Roman Kolesnikov

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1 Comment

Estus Flask Over a year ago

It is not obvious what is the lexical scope of doSomething. It has a good chance to not get 'correct this'. The problem the question wasn't specific enough at the moment of posting, and bad questions result in bad answers.

R. Richards · Accepted Answer · 2017-04-07 20:30:18Z

0

Another option with Angular, instead of adding an event listener to the document directly, is the @HostListener function decorator. Below is a sample. More information.

@HostListener('click', ['$event'])
onClick(event) : void {

    event.stopPropagation();

    if(...) {
        console.log(this.something);
    }
    else if (...) {
        ...
    }
}

Obviously, I don't know your whole situation, but something like this could be of use to you.

answered Apr 7, 2017 at 20:30

R. Richards

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