Correct syntax needed for bind() on 'this' object using class

I think as usual @allObjects has done an awesome job of answering the question about bind.

But looking at the code above, there are a few big issues that I thought it might help if I point out in-line:

class TestBind {
  constructor() {
    var vX = 23;  // This creates a LOCAL VARIABLE - you need this.vX=23;
  }
 
  getX() { 
    return this.vX; 
  }
  setX( obj ) {
    this.vX = obj;
  }
}
exports = TestBind; // not really useful in this case as you're using using 'TestBind' directly

var tb = new TestBind();
var g = tb.getX; // This makes 'g' equal to the function 'getX' itself
// Check out https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Functions/get for a real example of getters
print g // this is not how you call a function in JS. It won't print anything at all. You need print(g)


var tb = new TestBind();
tb.setX = 42; // This just overwrites the 'setX' function with the number 42
// Check out https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Functions/set for a real example of setters

var g = tb.getX(); // this works, there is no 'Function "getX" not found!' error so I can only assume you're not uploading the code that you posted

I'm not sure any of these problems you're having would be fixed by how you use bind though.

I think what you intended to do was probably:

class TestBind {
  constructor() {
    this.vX = 23;
  }
  getX() {
    return this.vX; 
  }
  setX( obj ) {
    this.vX = obj;
  }
}

var tb = new TestBind();
print(tb.getX()); // prints 23
var g = tb.getX();
print(g); // prints 23
tb.setX(42);
print(tb.getX()); // prints 42