function indexed( x, predicate, thisArg ) {
	var n;
	var i;

	n = 0;
	for ( i = 0; i < x.length; i++ ) {
		if ( predicate.call( thisArg, x[ i ], i, x ) ) {
			n += 1;
		}
	}
	return n;
}
Counts the number of elements in an indexed array which pass a test implemented by a predicate function.

@private
@param {Collection} x - input array
@param {Function} predicate - predicate function
@param {*} thisArg - predicate function evaluation context
@returns {NonNegativeInteger} result

@example
function predicate( value ) {
    return ( value > 0 );
}

var x = [ 0, 1, 0, 1, 1 ];

var n = indexed( x, predicate, {} );
// returns 3