Append an array to another array in JavaScript [duplicate]

Append an array to another array in JavaScript [duplicate]

This question is an exact duplicate of:
How to append an array to an existing JavaScript Array?

How do you append an array to another array in JavaScript?
Other ways that a person might word this question:

Add an array to another
Concat / Concatenate arrays
Extend an array with another array
Put the contents of one array into another array

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Solutions/Answers:

Solution 1:

If you want to modify the original array instead of returning a new array, use .push()

array1.push.apply(array1, array2);
array1.push.apply(array1, array3);

I used .apply to push the individual members of arrays 2 and 3 at once.

or…

array1.push.apply(array1, array2.concat(array3));

To deal with large arrays, you can do this in batches.

for (var n = 0, to_add = array2.concat(array3); n < to_add.length; n+=300) {
    array1.push.apply(array1, to_add.slice(n, n+300));
}

If you do this a lot, create a method or function to handle it.

var push_apply = Function.apply.bind([].push);
var slice_call = Function.call.bind([].slice);

Object.defineProperty(Array.prototype, "pushArrayMembers", {
    value: function() {
        for (var i = 0; i < arguments.length; i++) {
            var to_add = arguments[i];
            for (var n = 0; n < to_add.length; n+=300) {
                push_apply(this, slice_call(to_add, n, n+300));
            }
        }
    }
});

and use it like this:

array1.pushArrayMembers(array2, array3);
var push_apply = Function.apply.bind([].push);
var slice_call = Function.call.bind([].slice);

Object.defineProperty(Array.prototype, "pushArrayMembers", {
    value: function() {
        for (var i = 0; i < arguments.length; i++) {
            var to_add = arguments[i];
            for (var n = 0; n < to_add.length; n+=300) {
                push_apply(this, slice_call(to_add, n, n+300));
            }
        }
    }
});

var array1 = ['a','b','c'];
var array2 = ['d','e','f'];
var array3 = ['g','h','i'];

array1.pushArrayMembers(array2, array3);

document.body.textContent = JSON.stringify(array1, null, 4);