Gradient Animation Plugin

A lightweight, dependency-free JavaScript library for creating smooth CSS linear gradient transitions.

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Overview

Gradient Animation Plugin provides a powerful utility function that enables smooth, frame-by-frame transitions between CSS linear gradients. Unlike instant CSS changes, this plugin creates fluid animations by interpolating color values, positions, and angles over time using requestAnimationFrame for optimal performance.

Key Features

• Zero Dependencies — Pure vanilla JavaScript with no external libraries required
• Lightweight — Single function, minimal footprint (~3KB)
• Modern API — Clean options object with destructuring support
• Promise-based — Async/await compatible with completion callbacks
• Cancellable — Stop animations mid-flight with the cancel function
• Easing Support — Built-in easing functions for natural motion
• requestAnimationFrame — Smooth, 60fps animations synced to display refresh
• Full Control — Animate colors, positions, and gradient angles simultaneously
• ES6 Modules — Native import/export support

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Demo

Live Demo — Try it in your browser!

Transform your UI with smooth gradient transitions:

Before:  ████████████████  →  After:  ████████████████
         [Gold → Pink]              [Blue → Purple]
         180° angle                  270° angle

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Tech Stack

Technology	Purpose
JavaScript (ES6+)	Core animation logic with modern syntax
requestAnimationFrame	Smooth, performant animation loop
CSS3 Linear Gradients	Visual rendering with RGBA color support
ES6 Modules	Native import/export support

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Installation

ES6 Module (Recommended)

import changeGradient, { easings } from './gradient_plugin.js';

Script Tag (Legacy)

<script type="module">
  import changeGradient from './gradient_plugin.js';
  // Your code here
</script>

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Usage

Basic Syntax

const { promise, cancel } = changeGradient({
  element: '#hero-section',      // CSS selector or DOM element
  from: {
    colors: [[253, 183, 26], [211, 22, 131]],  // [top RGB, bottom RGB]
    positions: [0, 86],           // Color stop positions (%)
    angle: 180                    // Gradient angle (degrees)
  },
  to: {
    colors: [[66, 134, 244], [156, 39, 176]],
    positions: [0, 100],
    angle: 270
  },
  duration: 1000,                 // Animation duration (ms)
  easing: easings.easeInOutQuad   // Optional easing function
});

Using Promises

// Async/await
async function animateGradient() {
  const { promise } = changeGradient({
    element: '#background',
    from: {
      colors: [[255, 0, 0], [0, 0, 255]],
      positions: [0, 100],
      angle: 90
    },
    to: {
      colors: [[0, 255, 0], [255, 255, 0]],
      positions: [0, 100],
      angle: 180
    },
    duration: 2000
  });

  await promise;
  console.log('Animation complete!');
}

// Promise chain
changeGradient({ /* options */ })
  .promise
  .then(() => console.log('Done!'))
  .catch((err) => console.log('Cancelled:', err.message));

Cancelling Animations

const { promise, cancel } = changeGradient({
  element: '#hero',
  from: { colors: [[255, 0, 0], [0, 0, 255]], angle: 0 },
  to: { colors: [[0, 255, 0], [255, 255, 0]], angle: 360 },
  duration: 5000
});

// Cancel after 2 seconds
setTimeout(() => {
  cancel();
}, 2000);

// Handle cancellation
promise.catch((err) => {
  if (err.message === 'Animation cancelled') {
    console.log('Animation was cancelled');
  }
});

Using Easing Functions

import changeGradient, { easings } from './gradient_plugin.js';

// Available easings:
// - easings.linear (default)
// - easings.easeInQuad
// - easings.easeOutQuad
// - easings.easeInOutQuad
// - easings.easeInCubic
// - easings.easeOutCubic
// - easings.easeInOutCubic

changeGradient({
  element: '#box',
  from: { colors: [[100, 100, 100], [50, 50, 50]], angle: 45 },
  to: { colors: [[200, 100, 50], [150, 50, 100]], angle: 135 },
  duration: 1500,
  easing: easings.easeInOutCubic
});

// Or provide a custom easing function
changeGradient({
  element: '#box',
  from: { colors: [[100, 100, 100], [50, 50, 50]], angle: 45 },
  to: { colors: [[200, 100, 50], [150, 50, 100]], angle: 135 },
  duration: 1500,
  easing: (t) => 1 - Math.pow(1 - t, 3)  // Custom ease-out cubic
});

Complete HTML Example

<!DOCTYPE html>
<html>
<head>
  <style>
    #hero-section {
      width: 100%;
      height: 400px;
      background: linear-gradient(180deg, rgba(253,183,26,1) 0%, rgba(211,22,131,1) 86%);
    }
  </style>
</head>
<body>
  <div id="hero-section">
    <h1>Welcome</h1>
  </div>

  <script type="module">
    import changeGradient, { easings } from './gradient_plugin.js';

    // Animate on page load
    changeGradient({
      element: '#hero-section',
      from: {
        colors: [[253, 183, 26], [211, 22, 131]],
        positions: [0, 86],
        angle: 180
      },
      to: {
        colors: [[66, 134, 244], [156, 39, 176]],
        positions: [0, 100],
        angle: 270
      },
      duration: 1500,
      easing: easings.easeInOutQuad
    });
  </script>
</body>
</html>

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API Reference

changeGradient(options)

Creates a smooth gradient animation on the specified element.

Parameters

Option	Type	Required	Default	Description
element	String | Element	Yes	—	CSS selector or DOM element
from	Object	Yes	—	Starting gradient state
from.colors	Array<Array<number>>	Yes	—	RGB arrays [[R,G,B], [R,G,B]]
from.positions	Array<number>	No	[0, 100]	Color stop positions [0-100, 0-100]
from.angle	number	No	180	Gradient angle in degrees
to	Object	Yes	—	Ending gradient state
to.colors	Array<Array<number>>	Yes	—	RGB arrays [[R,G,B], [R,G,B]]
to.positions	Array<number>	No	[0, 100]	Color stop positions [0-100, 0-100]
to.angle	number	No	180	Gradient angle in degrees
duration	number	No	1000	Animation duration in milliseconds
easing	Function	No	linear	Easing function (t: number) => number

Returns

{
  promise: Promise<void>,  // Resolves when animation completes
  cancel: () => void       // Stops the animation immediately
}

easings

Object containing built-in easing functions:

Easing	Description
linear	Constant speed (default)
easeInQuad	Slow start, accelerating
easeOutQuad	Fast start, decelerating
easeInOutQuad	Slow start and end
easeInCubic	Slower start, more acceleration
easeOutCubic	Faster start, more deceleration
easeInOutCubic	Smoother slow start and end

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Use Cases

• Hero Sections — Create eye-catching animated backgrounds
• Theme Transitions — Smoothly switch between light/dark modes
• Interactive UI — Respond to user actions with gradient animations
• Loading States — Visual feedback during async operations
• Landing Pages — Add dynamic visual appeal to marketing pages
• Hover Effects — Animate gradients on user interaction

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Browser Support

Browser	Support
Chrome	Latest
Firefox	Latest
Safari	Latest
Edge	Latest
Opera	Latest

Requires ES6+ support (all modern browsers).

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Project Structure

gradient-animation/
├── README.md              # Documentation
└── gradient_plugin.js     # Core plugin (ES6 module)

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Skills Demonstrated

This project showcases proficiency in:

• Modern JavaScript (ES6+) — Arrow functions, destructuring, template literals, modules
• Animation APIs — requestAnimationFrame for smooth, performant animations
• Promise Patterns — Async/await, cancellation, error handling
• API Design — Clean options object pattern, sensible defaults
• CSS3 — Advanced gradient syntax and dynamic styling
• Algorithm Design — Time-based interpolation with easing functions

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Contributing

Contributions are welcome! Feel free to submit issues or pull requests.

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License

This project is open source and available under the MIT License.

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Author

Built with JavaScript and a passion for smooth user experiences.