
{{alias}}( x, mask, clbk[, thisArg] )
    Returns a new array by applying a mask to a provided input array
    and mapping the unmasked values according to a callback function.

    If a mask array element is falsy, the corresponding element in `x` is
    mapped in the output array; otherwise, the corresponding element in `x` is
    "masked" and thus excluded from the output array.

    Parameters
    ----------
    x: ArrayLikeObject
        Input array.

    mask: ArrayLikeObject
        Mask array.

    clbk: Function
        Mapping function.

    thisArg: any (optional)
        Execution context.

    Returns
    -------
    out: Array
        Output array.

    Examples
    --------
    > var x = [ 1, 2, 3, 4 ];
    > function clbk( val ) { return val * 2; }
    > var y = {{alias}}( x, [ 0, 1, 0, 1 ], clbk )
    [ 2, 6 ]


{{alias}}.assign( x, mask, out, stride, offset, clbk[, thisArg] )
    Applies a mask to a provided input array, maps the unmasked values
    according to a callback function, and assigns the unmasked values
    to elements in a provided output array.

    If a mask array element is falsy, the corresponding element in `x` is
    mapped and included in the output array; otherwise, the corresponding
    element in `x` is "masked" and thus excluded from the output array.

    Parameters
    ----------
    x: ArrayLikeObject
        Input array.

    mask: ArrayLikeObject
        Mask array.

    out: ArrayLikeObject
        Output array.

    stride: integer
        Output array stride.

    offset: integer
        Output array offset.

    clbk: Function
        Mapping function.

    thisArg: any (optional)
        Execution context.

    Returns
    -------
    out: ArrayLikeObject
        Output array.

    Examples
    --------
    > var x = [ 1, 2, 3, 4 ];
    > var m = [ 0, 1, 0, 1 ];
    > var out = [ 0, 0, 0, 0 ];
    > var scale = 5;
    > function clbk( val ) { return val * this; }
    > var arr = {{alias}}.assign( x, m, out, 2, 0, clbk, scale )
    [ 5, 0, 15, 0 ]
    > var bool = ( arr === out )
    true

    See Also
    --------
