Scaling between two number ranges

Question

I remember using an equation to do this at some point – how do you do this in Javascript?

Plugin two number ranges:

rangeX = 1 (through) 10;
rangeY =         


        

Answer 1

Swift 3 With Bool for extended range or not

func translate(input : Float, inputMin: Float, inputMax: Float, outputMin: Float, outputMax: Float, extendRange: Bool? = false, log: Bool? = false) -> Float {

    //The actual translation function
    func translationResult(_ inputMinA: Float, _ inputMaxA: Float) -> Float {
        let myResult = outputMin + (outputMax - outputMin) * (input - inputMinA) / (inputMaxA - inputMinA)
        return myResult
    }

    // extendRange true means it'll return a value outside the range of inputMin and inputMax but still follow the ratio
    if extendRange! {
        return result = translationResult(inputMin, inputMax)

        if log! == true && input > inputMax || input < inputMin{
            print("outside range!")
        }
    } else {
        //Doesn't let value go outside range
        let inputMinA = min(inputMin, input)
        let inputMaxA = max(inputMax, input)

        return result = translationResult(inputMinA, inputMaxA)
    }
    }


    translate(input: 50, inputMin: 100, inputMax: 1000.0, outputMin: 1, outputMax: 10, extendRange: false) => 1
    translate(input: 50, inputMin: 100, inputMax: 1000.0, outputMin: 1, outputMax: 10, extendRange: true) => 0.5