function incrmsumabs( W ) {
	var sum;
	if ( !isPositiveInteger( W ) ) {
		throw new TypeError( format( 'invalid argument. Must provide a positive integer. Value: `%s`.', W ) );
	}
	sum = incrmsum( W );
	return accumulator;

	/**
	* If provided a value, the accumulator function returns an updated sum. If not provided a value, the accumulator function returns the current sum.
	*
	* @private
	* @param {number} [x] - input value
	* @returns {(number|null)} sum or null
	*/
	function accumulator( x ) {
		if ( arguments.length === 0 ) {
			return sum();
		}
		return sum( abs( x ) );
	}
}
Returns an accumulator function which incrementally computes a moving sum of absolute values.

@param {PositiveInteger} W - window size
@throws {TypeError} must provide a positive integer
@returns {Function} accumulator function

@example
var accumulator = incrmsumabs( 3 );

var sum = accumulator();
// returns null

sum = accumulator( 2.0 );
// returns 2.0

sum = accumulator( -5.0 );
// returns 7.0

sum = accumulator( 3.0 );
// returns 10.0

sum = accumulator( 5.0 );
// returns 13.0

sum = accumulator();
// returns 13.0