@dooboostore/lib-node

Full Documentation: https://dooboostore-develop.github.io/@dooboostore/lib-node

A Node.js utility package for generating random placeholder images using server-side canvas.

Features

• Generate random image compositions with shapes (circle, rectangle, triangle, star).
• Export as Buffer for direct upload/response pipelines.
• Export as Base64 data URL for inline preview use cases.
• Save output to disk with sync or async file APIs.
• Root-first and bundle-entry import support.

Installation

# pnpm
pnpm add @dooboostore/lib-node

# npm
npm install @dooboostore/lib-node

# yarn
yarn add @dooboostore/lib-node

Public API

@dooboostore/lib-node exposes:

• RandomImage

Import Guide

Root import (recommended)

import { RandomImage } from '@dooboostore/lib-node';

Bundle entry import

import { RandomImage } from '@dooboostore/lib-node/bundle-entry';

Basic Usage

import { RandomImage } from '@dooboostore/lib-node';
import * as path from 'path';

async function generateImage() {
  const randomImage = new RandomImage();
  const filePath = path.join(__dirname, 'my-random-image.png');

  await randomImage.writeFile({
    path: filePath,
    size: { w: 200, h: 200 },
    mimeType: 'image/png'
  });

  console.log(`Image saved to ${filePath}`);
}

generateImage();

API Reference

RandomImage

buffer(config)

Returns image bytes as Buffer.

const image = new RandomImage();
const buffer = image.buffer({
  size: { w: 400, h: 240 },
  mimeType: 'image/png'
});

base64(config)

Returns a Base64 data URL string.

const image = new RandomImage();
const base64 = image.base64({
  size: { w: 300, h: 300 },
  mimeType: 'image/jpeg',
  quality: 0.9
});

writeFile(config)

Writes image to disk asynchronously.

await new RandomImage().writeFile({
  path: './out/random-image.png',
  size: { w: 512, h: 512 },
  mimeType: 'image/png'
});

writeFileSync(config)

Writes image to disk synchronously.

new RandomImage().writeFileSync({
  path: './out/random-sync.jpg',
  size: { w: 256, h: 256 },
  mimeType: 'image/jpeg'
});

Configuration Shape

All methods use a variant of this config:

{
  size: { w: number; h: number; },
  mimeType?: 'image/png' | 'image/jpeg',
  quality?: number,        // only for jpeg base64 output
  path?: string            // required for writeFile/writeFileSync
}

Typical Use Cases

• Generating placeholder images for test fixtures.
• Producing random thumbnails for QA/demo data.
• Returning generated image data from Node HTTP endpoints.
• Batch image generation in scripts.

Troubleshooting

Issue: canvas install/build fails on CI or local machine
Solution: install platform build dependencies required by canvas before package install.

Issue: Output looks too compressed in JPEG mode
Solution: raise quality value in base64({ mimeType: 'image/jpeg', quality }).

Issue: File write fails with ENOENT
Solution: create parent directories before calling writeFile/writeFileSync.

Learn More

The detailed API documentation is available on our documentation website.

Related Packages

• @dooboostore/core
• @dooboostore/core-node
• @dooboostore/lib-web

License

This package is licensed under the MIT License.