function roundb( x, n, b ) {
	var y;
	var s;
	if (
		isnan( x ) ||
		isnan( n ) ||
		isnan( b ) ||
		b <= 0 ||
		isInfinite( n ) ||
		isInfinite( b )
	) {
		return NaN;
	}
	if ( isInfinite( x ) || x === 0.0 ) {
		return x;
	}
	if ( b === 10 ) {
		return roundn( x, n );
	}
	if ( n === 0 || b === 1 ) {
		return round( x );
	}
	s = pow( b, -n );

	// Check for overflow:
	if ( isInfinite( s ) ) {
		return x;
	}
	y = round( x * s ) / s;

	// Check for overflow:
	if ( isInfinite( y ) ) {
		return x;
	}
	return y;
}
Rounds a numeric value to the nearest multiple of \\(b^n\\) on a linear scale.

@param {number} x - input value
@param {integer} n - integer power
@param {PositiveInteger} b - base
@returns {number} rounded value

@example
// Round a value to 2 decimal places:
var v = roundb( 3.141592653589793, -2, 10 );
// returns 3.14

@example
// If n = 0 or b = 1, `roundb` behaves like `round`:
var v = roundb( 3.141592653589793, 0, 2 );
// returns 3.0

@example
// Round a value to the nearest multiple of two:
var v = roundb( 5.0, 1, 2 );
// returns 6.0