Move item in array to last position

to move an element (of which you know the index) to the end of an array, do this:

array.push(array.splice(index, 1)[0]);

If you don’t have the index, and only the element, then do this:

array.push(array.splice(array.indexOf(element), 1)[0]);

Example:

    var arr = [1, 2, 6, 3, 4, 5];
    arr.push(arr.splice(arr.indexOf(6), 1)[0]);
    console.log(arr); // [1, 2, 3, 4, 5, 6]

NOTE:

this only works with Arrays (created with the [ ... ] syntax or
Array()) not with Objects (created with the { ... } syntax or
Object())