What is animejs?

AnimeJS is a lightweight JavaScript library that makes it easy to create animations on web pages. Think of it as a toolbox that lets you move, fade, scale, rotate, or change any HTML, CSS, SVG, or DOM element with just a few lines of code. It works in the browser, doesn’t need any extra plugins, and is designed to be simple enough for beginners while still powerful for advanced users.

Let's break it down

  • Core idea: You tell AnimeJS what you want to animate (the target), what properties to change (like opacity, translateX, scale), and how long it should take.
  • Syntax: A typical call looks like anime({ targets: '.box', translateX: 250, duration: 1000, easing: 'easeOutQuad' });
  • Key parts:
  • targets - the element(s) you want to animate, selected with CSS selectors or DOM references.
  • properties - the CSS or SVG attributes you want to modify (e.g., opacity, rotate, strokeDashoffset).
  • duration - how many milliseconds the animation runs.
  • easing - the speed curve that makes the motion feel natural (e.g., linear, easeInOut, spring‑like).
  • loop - repeat the animation forever or a set number of times.
  • callbacks - functions that run at the start, each update, or the end of the animation.

Why does it matter?

Animations improve user experience by giving visual feedback, guiding attention, and making interfaces feel more responsive. Without a library, you’d have to write complex CSS keyframes or manage requestAnimationFrame manually. AnimeJS abstracts that complexity, letting you focus on what should happen rather than how to calculate each frame. This speeds up development, reduces bugs, and creates smoother, more consistent animations across browsers.

Where is it used?

  • Interactive websites that need hover effects, scroll‑based reveals, or loading spinners.
  • Single‑page applications (React, Vue, Angular) where components animate in and out.
  • Data visualizations and dashboards that animate charts, graphs, or numbers.
  • Mobile‑friendly web apps that need touch‑responsive motion.
  • Prototyping tools and code‑playgrounds where quick visual feedback is essential.

Good things about it

  • Small size: Only about 15 KB gzipped, so it doesn’t bloat page load.
  • Easy syntax: Very readable code, perfect for beginners.
  • Versatile: Works with CSS, SVG, DOM attributes, and even JavaScript objects.
  • Rich easing library: Over 30 built‑in easing functions plus custom cubic‑bezier support.
  • Timeline feature: Lets you chain multiple animations with precise control over timing.
  • No dependencies: Pure JavaScript, no need for jQuery or other libraries.

Not-so-good things

  • Limited to front‑end: It only animates what the browser can render; it can’t control server‑side or native app animations.
  • Learning curve for complex timelines: While basic usage is simple, mastering nested timelines and synchronizing many elements can become tricky.
  • Performance considerations: Overusing many simultaneous animations can affect battery life on mobile devices; you still need to follow best practices (e.g., animate transforms and opacity).
  • Less community support than massive frameworks: Compared to GreenSock (GSAP), AnimeJS has fewer tutorials and plugins, so finding niche solutions may require more digging.