I want to use `=` to initiate an array in a function. However, `=` cannot change the array, but `push` can.

I want it equals to `["a", "b"]`. But now the result is `["1", "2"]`.

I tried `arr = ['a', 'b'];` and also `arr = ['a', 'b'].slice();`. But neither works.

How can I let `=` work in this case?

```
var array = [];

init(array);
console.log(array);

function init(arr) {
  arr.push('1');
  arr.push('2');
  arr = ['a', 'b'];
}

```

<https://jsbin.com/kiveyu/4/edit?js,console>