A generator function that returns an Array consisting of [index, element]. Behaves like the Python function.

enumerate.js

function* enumerate(array)
{
    /**
     * Duplicates the functionality of Python's enumerate function.
     *
     * Return, for each element of 'array' an array the element's index and the element.
     *
     * e.g.
     *
     *  [i, elem]
     *
     * :param: array: (Array) Any array.
     *
     * :yield: For each element of 'array' this generator function will yield an Array of the form
     *      [<element index≥, element]
     */

    let counter = 0;

    for (let element of array)
        yield [counter++, element];
}