Documentation

css

Animate the CSS values of a DOM element.

animol.css(
  element: Element,
  duration: number, // milliseconds
  from: Object, // Default: {}
  to: Object, // Default: {}
  easing: (number) => number, // Default: animol.Easing.easeInOutQuad
  delay: number // milliseconds, default: 0
);
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The from and to parameters are objects where the keys are CSS properties written in camel case.

import * as animol from 'animol';

const myElement = document.getElementById('my-element');

animol.css(
  myElement,
  1000,
  { height: '100px' },
  { height: '200px' }
);
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CSS transforms are supported. The transform value should be an object where the keys are CSS transform functions. The functions will always be applied in this order: translate, scale, rotate. You cannot use convenience functions such as translate and scale; you must use translateX and scaleY (for example).

animol.css(
  myElement,
  1000,
  { transform: { translateX: '-100%', rotate: '0deg' } },
  { transform: { translateX: '100%', rotate: '50deg' } },
);
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3D transforms are also supported:

animol.css(
  myElement,
  3000,
  { transform: { rotateY: '0deg', rotateZ: '0deg' } },
  { transform: { rotateY: '360deg', rotateZ: '90deg' } },
  animol.Easing.easeInOutElastic(1.5),
);
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The css function will try to infer the value of a style if you don't explicitly provide it, based on the computed style of the element. Accordingly, it's ok to do things like this:




 



animol.css(
  myElement,
  1000,
  {},
  { transform: { translateX: '100px' } }
);
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ease

Animate any value with an easing function. The callback will be called each animation frame and receives a "progress" parameter which is a number between 0 and 1.

animol.ease(
  callback: (number) => void,
  duration: number, //milliseconds
  easing: (number) => number,
  delay: number // milliseconds
);
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The ease function can be used to animate DOM element attributes (among other things).

animol.ease(
  (progress) => {
    myElement.setAttribute('stroke-dashoffset', `${1000 - (progress * 1000)}`)
  },
  2000
);
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Easing

Animol exposes a number of standard easing functions that you can pass into css and ease.








 


import * as animol from 'animol';

animol.css(
  myElement,
  1000,
  { height: '100px' },
  { height: '200px' },
  animol.Easing.easeInOutBack
);
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Some common easing functions are attached to the Easing property:

linear
easeInQuad
easeOutQuad
easeInOutQuad
easeInCubic
easeOutCubic
easeInOutCubic
easeInQuart
easeOutQuart
easeInOutQuart
easeInQuint
easeOutQuint
easeInOutQuint
easeInElastic
easeOutElastic
easeInOutElastic
easeInBack
easeOutBack
easeInOutBack
easeInBounce
easeOutBounce
easeInOutBounce
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For elastic and back easing functions you must pass in the power of the animation, e.g.

animol.Easing.easeInOutElastic(1.5) // Power of 1 is the default
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You can also provide a custom easing function where the parameter and return value are each numbers between 0-1.

parseColor

Parses a color string (hex, rgb, or rgba) into an array [red, green, blue, alpha].

animol.parseColor(
  color: string // rgb, rgba, or hex
): Array<number>;
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blend

Blends two color arrays linearly and returns a color string in rgba form;

animol.blend(
  fromColor: Array<number>,
  toColor: Array<number>,
  ratio: number
): string;
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You can use parseColor and blend together to interpolate between colors.

const red = animol.parseColor('#FF0000');
const blue = animol.parseColor('#0000FF');
const purple = animol.blend(red, blue, 0.5); // 'rgba(128, 0, 128, 1)'
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promise

The css and ease functions return return an object which has a promise property that is (surprise!) a Promise. This allows you to do something after the animation completes. For example:









 










const myAnimation = animol.css(
  myElement,
  2000,
  { transform: { translateX: '0px' } },
  { transform: { translateX: '200px' } },
  animol.Easing.easeInOutCubic,
);

myAnimation.promise.then(() => {
  // Start a new animation after the initial one finishes
  animol.css(
    myElement,
    2000,
    { transform: { translateX: '200px' } },
    { transform: { translateX: '100px' } },
    animol.Easing.easeInOutCubic,
  );
});
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cancel

Animation objects returned by css and ease can also be cancelled by calling the cancel function. This will stop the animation and cause the promise to reject.









 

const myAnimation = animol.css(
  myElement,
  2000,
  { marginLeft: '0px' },
  { marginLeft: '200px' },
  animol.Easing.easeInOutCubic,
);

myAnimation.cancel();
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Gotchas

Convenience properties and functions such as background, border, padding and translate are not supported. Use the individual values like backgroundColor, borderWidth, paddingLeft and translateX instead. Similarly, you can't use color shorthands like black or IndianRed.

Animol cannot convert between units. For example, the following will throw an error:

animol.css(
  myElement,
  2000,
  { height: '100px' },
  { height: '50em' },
);
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