D3.js developers released their scaling functions into a separate package. I recommend to use these instead. d3-scale

Scale number

Let's you map a number from a range to another.

---

Current status: Alpha, API might change until 1.0.0

Scales

createLinearScale(fromRange, toRange)

Returns a scaling function from an input range to an output range.

Ranges are expressed with arrays.

var scaleNumber = require('scale-numbers')
var scale = scaleNumber.createLinearScale([10, 20], [100, 200])

var number = scale(15)
console.log(number) // 150

If the value is out of the entry range, it will be mapped to the lowest or greatest value. (this behaviour might be available as an option later)

var scale = scaleNumber.createLinearScale([10, 20], [100, 200])

var number = scale(5)
console.log(number) // 100

Story

This project gets its inspiration from d3 scale.

https://github.com/mbostock/d3/wiki/Quantitative-Scales

I needed this functionality as stand alone.

Roadmap

done

• linear scale

todo

• other type of scales and options like logarithmic, discrete, rounded, etc.