@bluehexagons/easing

A simple easing library.

All functions expect a time constraint of [0-1].

Code heavily-adapted from https://github.com/jimjeffers/Easie which is itself adapted from http://robertpenner.com/easing

MIT license.

Installation

npm install @bluehexagons/easing

Usage

import { lerp, ease, quadIn, linear, elasticInOut } from '@bluehexagons/easing';
// commonjs: const { lerp, ease, quadIn, linear, elasticInOut } = require('@bluehexagons/easing');

const time = 0.5;
const start = 0;
const end = 100;

// Linearly interpolate between a start and end value
console.log(
  lerp(time, start, end)
);

// Apply an EasingFunction to interpolate between start and end values
console.log(
  ease(quadIn, time, start, end)
);

// Use an EasingFunction directly
console.log(
  linear(time)
);

// elasticInOut is a more complicated easing function
const amplitude = 1.5;
const period = 0.3;
console.log(
  elasticInOut(time, amplitude, period)
);

// Using elasticInOut with the ease helper function, if you really want to
console.log(
  ease(t => elasticInOut(t, amplitude, period), time, start, end)
);

// Or the ease helper function on its own
console.log(
  ease(t => t ** 2, time, start, end)
);

CommonJS

TypeScript is used to compile a commonjs version of this module.

Import with, e.g., const Easing = require('@bluehexagons/easing).

Contributing

Pull requests are welcome.

TypeScript

src/main.d.mts contains typings.

To build TypeScript definitions for development, run npm run build