This is a set of easing equations which are outside of standard Penner easing equations

Usage no npm install needed!

<script type="module">
  import easesFancy from 'https://cdn.skypack.dev/eases-fancy';




This is a set of easing equations which are outside of standard Penner easing equations.


You can require in individual functions using require statements before or access them directly by requiring in 'eases-fancy'.


var mod = require('ease-fancy/mod');
// or by doing
var mod = require('eases-fancy').mod;


var bezier = require('eases-fancy/bezier')([opts])


Above rendering a custom bezier curve

This function will return an ease equation based on a cubic bezier curve.

It should be noted this simply wraps the cubic-bezier module to have a consistent api with the rest of the fancy eases.

Optionally you can pass in the following options:

  • points an array of four numbers which represent a cubic bezier curve default [0.21,1.08,1,-0.96]
  • precision the higher the value the more precise the curve will be default value 1000.

var points = require('eases-fancy/points')([opts])


Will render a series points which define an easing equation


This is the exact same graph as above with an elastic out ease equation added to the second keyframe

Returns a function that will perform eases based on custom points you've passed in.


  • points a two dimensional array that is formatted in the following way:
    [ value, time, ease ],
    [ value, time, ease ],
    [ value, time, ease ]

In the above arrays value is a value the interpolation amount at the time defined by time and ease is an optional ease function which will be used to to the following key frame. values's are typically between 0-1 however values less than 0 or greater than 1 are also acceptable. Optionally an ease function can be passed as the third parameter for more complex graphs.

var pointsRandom = require('eases-fancy/points-random')([opts])

random quint

The above is rendering the quint function randomized

random quint

The above is rendering 100 randomized points which for an ease equation which taper out

Options which can be passed to points-random:

  • numPoints this is how many random points you'd like to add. Default 20
  • offset this value is how offset each random point is off the original ease quation. Default 0.3
  • ease the base ease equation to randomize from. Default is a linear ease equation.

var stepped = require('eases-fancy/stepped')([opts])


Rendering with two steps

stepped expo

Rendering with two steps and ease expo

Returns an easing function for stepped eases with the following optional options:

  • steps the number of steps you'd like to have. The above is with two steps. Default value 1
  • ease an ease equation which will modify the original steps.

var quantize = require('eases-fancy/quantize')([opts])


Rendering quantize with a linear interpolated graph


Rendering quantize with a custom ease using the above mentioned points

quantize will make all values be either 0 or 1. This could be used for instance to blink on and off something.


  • ease an ease function we'd like to quantize. Default linear
  • edge a threshould value from which to either set values to 0 or 1. For instance if edge is 0.3 all values less than 0.3 will produce 0 and all values greater will produce 1. Default 0.5.

var mod = require('eases-fancy/mod')([opts])


Rendering mod with defaults. (repeats linear ease over and over)


Rendering mod with a custom ease.

mod will repeat an ease function the number of times you ask it to.

Options for mod:

  • ease ease function which will be repeated. Default linear.
  • repeat count times you'd like to repeat the ease function. Default 5


MIT, see LICENSE.md for details.