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gentleduck lazy

gentleduck lazy

It is a lightweight and accessible React library for lazy-loading images and components. It uses the IntersectionObserver API to trigger loading when content enters the viewport, ensuring smooth performance and accessibility.

Features

  • Lazy loading for components and images
  • Customizable with IntersectionObserver options
  • Accessibility-first: ARIA roles, live regions, focus management
  • Placeholder support while content loads
  • Composable hooks for custom behavior

Installation

npm install @gentleduck/lazy
npm install @gentleduck/lazy

Usage

1) Lazy Component

The DuckLazyComponent defers rendering until its children enter the viewport.

import { DuckLazyComponent } from '@gentleduck/lazy'
 
function MyComponent() {
  return (
    <DuckLazyComponent options={{ rootMargin: '100px', threshold: 0.25 }}>
      <div>Content that will be lazily loaded</div>
    </DuckLazyComponent>
  )
}
import { DuckLazyComponent } from '@gentleduck/lazy'
 
function MyComponent() {
  return (
    <DuckLazyComponent options={{ rootMargin: '100px', threshold: 0.25 }}>
      <div>Content that will be lazily loaded</div>
    </DuckLazyComponent>
  )
}

Props

  • options?: IntersectionObserver options (rootMargin, threshold)
  • children: The lazy-loaded content

2) Lazy Image

The DuckLazyImage supports placeholders, accessibility attributes, and Next.js next/image.

import { DuckLazyImage } from '@gentleduck/lazy'
 
function MyImageComponent() {
  return (
    <DuckLazyImage
      src="https://example.com/image.jpg"
      placeholder="https://example.com/placeholder.jpg"
      alt="A description of the image"
      width={400}
      height={300}
      options={{ rootMargin: '100px', threshold: 0.25 }}
    />
  )
}
import { DuckLazyImage } from '@gentleduck/lazy'
 
function MyImageComponent() {
  return (
    <DuckLazyImage
      src="https://example.com/image.jpg"
      placeholder="https://example.com/placeholder.jpg"
      alt="A description of the image"
      width={400}
      height={300}
      options={{ rootMargin: '100px', threshold: 0.25 }}
    />
  )
}

Props

  • src: URL of the image (required)
  • placeholder?: Placeholder URL while loading
  • alt: Accessible description (required)
  • width / height: Image size (required)
  • options?: IntersectionObserver options
  • nextImage?: Enables Next.js next/image optimization

3) useLazyLoad Hook

Attach lazy-loading behavior to any element.

import { useLazyLoad } from '@gentleduck/lazy'
 
function MyComponent() {
  const { isVisible, elementRef } = useLazyLoad({
    rootMargin: '100px',
    threshold: 0.25,
  })
 
  return (
    <div ref={elementRef}>
      {isVisible ? <div>Visible content</div> : <div>Loading...</div>}
    </div>
  )
}
import { useLazyLoad } from '@gentleduck/lazy'
 
function MyComponent() {
  const { isVisible, elementRef } = useLazyLoad({
    rootMargin: '100px',
    threshold: 0.25,
  })
 
  return (
    <div ref={elementRef}>
      {isVisible ? <div>Visible content</div> : <div>Loading...</div>}
    </div>
  )
}

Returns

  • isVisible: boolean → if element is visible
  • elementRef: React.Ref → attach to observed element

4) useLazyImage Hook

Specialized hook for images: manages visibility + load state.

import { useLazyImage } from '@gentleduck/lazy'
 
function LazyImage({ src, placeholder }) {
  const { isLoaded, imageRef } = useLazyImage(src, {
    rootMargin: '100px',
    threshold: 0.25,
  })
 
  return (
    <div ref={imageRef}>
      {!isLoaded && <img src={placeholder} alt="Placeholder" />}
      {isLoaded && <img src={src} alt="Main Image" />}
    </div>
  )
}
import { useLazyImage } from '@gentleduck/lazy'
 
function LazyImage({ src, placeholder }) {
  const { isLoaded, imageRef } = useLazyImage(src, {
    rootMargin: '100px',
    threshold: 0.25,
  })
 
  return (
    <div ref={imageRef}>
      {!isLoaded && <img src={placeholder} alt="Placeholder" />}
      {isLoaded && <img src={src} alt="Main Image" />}
    </div>
  )
}

Returns

  • isLoaded: boolean → if image finished loading
  • imageRef: React.Ref → attach to <img>

DuckLazyImage Component (Detailed)

Optimized lazy image loader with placeholder + accessibility.

import { DuckLazyImage } from '@gentleduck/lazy'
 
function MyImageComponent() {
  return (
    <DuckLazyImage
      src="https://example.com/image.jpg"
      placeholder="https://example.com/placeholder.jpg"
      alt="Mountain view"
      width={400}
      height={300}
      options={{ rootMargin: '100px', threshold: 0.25 }}
    />
  )
}
import { DuckLazyImage } from '@gentleduck/lazy'
 
function MyImageComponent() {
  return (
    <DuckLazyImage
      src="https://example.com/image.jpg"
      placeholder="https://example.com/placeholder.jpg"
      alt="Mountain view"
      width={400}
      height={300}
      options={{ rootMargin: '100px', threshold: 0.25 }}
    />
  )
}

Integration with Next.js

Enable Next.js image optimization with nextImage.

<DuckLazyImage
  nextImage
  src="https://example.com/image.jpg"
  placeholder="https://example.com/placeholder.jpg"
  alt="Next.js optimized image"
  width={400}
  height={300}
/>
<DuckLazyImage
  nextImage
  src="https://example.com/image.jpg"
  placeholder="https://example.com/placeholder.jpg"
  alt="Next.js optimized image"
  width={400}
  height={300}
/>

Benefits:

  • Built-in Next.js optimization
  • Seamless lazy loading

Integration with React

Works as a drop-in replacement for <img> in plain React apps.

<DuckLazyImage
  src="https://example.com/image.jpg"
  placeholder="https://example.com/placeholder.jpg"
  alt="React lazy image"
  width={400}
  height={300}
/>
<DuckLazyImage
  src="https://example.com/image.jpg"
  placeholder="https://example.com/placeholder.jpg"
  alt="React lazy image"
  width={400}
  height={300}
/>

Accessibility Features

  • aria-live="polite" → announces loading state
  • aria-hidden → hides placeholders from AT
  • role="img" + aria-label for screen readers
  • aria-atomic + aria-relevant for granular updates
JavaScriptGentleduck Variants