transform can map an input value from one range of values to another.

const numberToColor = transform(
  [0, 100], // Input
  ["#000", "#fff"] // Output
)

numberToColor(50) // rgba(128, 128, 128, 1)

Usage

Import transform from Motion.

import { transform } from "motion"

Note: React users can also use the useTransform hook for use with motion values.

A transformation function can be created by passing two ranges, an input range and an output range:

const transformer = transform([0, 100], [0, 360])

The transformer can now be called with an input value:

transformer(50) // 180

Note:

• Both ranges must always be the same length.

• The input range must always be a linear series of numbers, either counting up or counting down.

• The output range can be a non-linear series of numbers, colors, or complex strings.

The input and output ranges can accept any number of values:

const x = [-100, 0, 100, 200]
const opacity = [0, 1, 1, 0]
const transformer = transform(x, opacity)

transformer(-50) // 0.5
transformer(50) // 1
transformer(150) // 0.5

If clamp: false is provided, the returned function will map infinitely:

const transformer = transform([0, 100], [0, 360], { clamp: false })

const rotation = transformer(200) // 720