`this` in callback points to wrong object

Question

I have this viewModel:

import app = require(\"durandal/app\");
import appViewModel = require(\"appViewModel\");
import dataService = require(\"dataService\");

c         


        

Answer 1

You could also do then(this.activateView.bind(this))

Answer 2

Since you are passing the function to someone else to call in .then(this.activateView); you need to preserve the context yourself, best if you do : .then((view)=>this.activateView(view));

More about this : https://www.youtube.com/watch?v=tvocUcbCupA

Answer 3

While you have your answer, the way I prefer is a bit different:

convert function/method definition - into "property referencing function"

// instead of class method
// public activateView(view) {

// use the "property"
public activateView = (view) => {
    this.activeScreen(view);
}

That will reduce the need to pass explicit params like this

.then((view) => this.activateView(view))

because this will work again:

.then(this.activateView)