function indexed( x, mask, out, stride, offset, clbk, thisArg ) {
	var io;
	var i;

	io = offset;
	for ( i = 0; i < x.length; i++ ) {
		if ( !mask[ i ] ) {
			out[ io ] = clbk.call(thisArg, x[ i ], i, x );
			io += stride;
		}
	}
	return out;
}
Applies a mask to an indexed array, maps the unmasked values according to a callback function, and assigns to elements in an indexed output array.

@private
@param {Collection} x - input array
@param {IntegerArray} mask - mask array
@param {Collection} out - output array
@param {integer} stride - output array stride
@param {NonNegativeInteger} offset - output array offset
@param {Function} clbk - function to apply
@param {*} [thisArg] - function context
@returns {Collection} output array

@example
var x = [ 1, 2, 3, 4 ];
var mask = [ 0, 1, 0, 1 ];

var out = [ 0, 0, 0, 0 ];

var arr = indexed( x, mask, out, 1, 0, function( val ) {
    return val * 2;
} );
// returns [ 2, 6, 0, 0 ]