Append / prepend items to array

Unshift

Use .unshift to add one or more items in the beginning of an array.

For example:

var array = [3, 4, 5, 6];
array.unshift(1, 2);

array results in:

[1, 2, 3, 4, 5, 6]

Push

Further .push is used to add items after the last currently existent item.

For example:

var array = [1, 2, 3];
array.push(4, 5, 6);

array results in:

[1, 2, 3, 4, 5, 6]

Both methods return the new array length.