randByPower.js

randByPower.js

function randByPower( min, max, power, rfc = randFc ) {
	if( min == max ) {
		return min
	}
	const value = rfc() * ( max - min ) + min
	return mapToPower( value, min, max, power )
}


function sign( value ) {
	return value != 0 ? ( value < 0 ? -1 : 1 ) : 0;
}

function mapToPower( value, min, max, power ) {
	const valueSign = sign( value )

	power = Math.abs( power )

	value = ( value - min ) / ( max - min )
	value = valueSign > 0 ? value : value - 1
	value = Math.pow( value * valueSign, Math.abs( power ) )
	value = valueSign > 0 ? value : 1 - value

	return value * ( max - min ) + min
}