{{alias}}( collection, [options,] groups )
    Groups values as arrays associated with distinct keys.

    If provided an empty collection, the function returns an empty object.

    Parameters
    ----------
    collection: Array|TypedArray|Object
        Input collection to group. If provided an object, the object must be
        array-like (excluding strings and functions).

    options: Object (optional)
        Options.

    options.returns: string (optional)
        If `values`, values are returned; if `indices`, indices are returned; if
        `*`, both indices and values are returned. Default: 'values'.

    groups: Array|TypedArray|Object
        A collection defining which group an element in the input collection
        belongs to. Each value in `groups` should resolve to a value which can
        be serialized as an object key. If provided an object, the object must
        be array-like (excluding strings and functions).

    Returns
    -------
    out: Object
        Group results.

    Examples
    --------
    > var collection = [ 'beep', 'boop', 'foo', 'bar' ];
    > var groups = [ 'b', 'b', 'f', 'b' ];
    > var out = {{alias}}( collection, groups )
    { 'b': [ 'beep', 'boop', 'bar' ], 'f': [ 'foo' ] }
    > groups = [ 1, 1, 2, 1 ];
    > out = {{alias}}( collection, groups )
    { '1': [ 'beep', 'boop', 'bar' ], '2': [ 'foo' ] }

    // Output group results as indices:
    > groups = [ 'b', 'b', 'f', 'b' ];
    > var opts = { 'returns': 'indices' };
    > out = {{alias}}( collection, opts, groups )
    { 'b': [ 0, 1, 3 ], 'f': [ 2 ] }

    // Output group results as index-element pairs:
    > opts = { 'returns': '*' };
    > out = {{alias}}( collection, opts, groups )
    { 'b': [ [0, 'beep'], [1, 'boop'], [3, 'bar'] ], 'f': [ [2, 'foo'] ] }

    See Also
    --------