function incrnancount() {
	var count = 0;
	return accumulator;

	/**
	* If provided a value, the accumulator function returns an updated count. If not provided a value, the accumulator function returns the current count.
	*
	* @private
	* @param {number} [x] - new value
	* @returns {number} count
	*/
	function accumulator( x ) {
		if ( arguments.length === 0 ) {
			return count;
		}
		if ( isnan( x ) === false ) {
			count += 1;
		}
		return count;
	}
}
Returns an accumulator function which incrementally updates a count, ignoring `NaN` values.

@returns {Function} accumulator function

@example
var accumulator = incrnancount();

var count = accumulator();
// returns 0

count = accumulator( 2.0 );
// returns 1

count = accumulator( -5.0 );
// returns 2

count = accumulator();
// returns 2