Link to array push function

Question

Basically why I can't do this:

var a = [];
var b = a.push;
b(1);

it give's error, I know how to avoid this, but why this is not working in js?

Because the value of `this` is determined at call time. However, you dissassociate the call from `a`. Therefore, there is no `this` value when `b()` (which is a reference to `Array.prototype.push` is called, so there is nothing to push *to*. — VLAZ, Jul 01 '21 at 18:22

score 1 · Answer 1 · answered Jul 01 '21 at 18:23

1

The this value is determined by how the function is called. You can use Function#bind to ensure the this value is set.

var a = [];
var b = a.push.bind(a);
b(1);
console.log(a);

answered Jul 01 '21 at 18:23

Unmitigated

score -1 · Answer 2 · answered Jul 01 '21 at 18:23

-1

Try this:

var a = [];
var b = (param) => a.push(param);
b(1);

answered Jul 01 '21 at 18:23

eagercoder

2 Answers2