@lopatnov/worker-from-string

A library that converts string values into Web Worker objects in the browser. Create dynamic Web Workers at runtime without separate script files.

Table of Contents

• Installation
• Usage
• API
• Examples
• Demo
• Contributing
• Built With
• License

Installation

npm install @lopatnov/worker-from-string

Browser (CDN):

<!-- Development version -->
<script src="https://lopatnov.github.io/worker-from-string/dist/worker-from-string.js"></script>

<!-- Production (minified) version -->
<script src="https://lopatnov.github.io/worker-from-string/dist/worker-from-string.min.js"></script>

Usage

ES Modules

import workerFromString from "@lopatnov/worker-from-string";

CommonJS

const workerFromString = require("@lopatnov/worker-from-string");

Browser (UMD)

const workerFromString = window.workerFromString;

API

workerFromString(...textValues: string[]): Worker

Creates a Web Worker from string values.

| Parameter | Type | Description | |--------------|------------|------------------------------------------------| | textValues | string[] | One or more strings containing the worker code |

Returns: Worker — a new Web Worker instance.

Examples

Basic Usage

const workerCode = `
  self.onmessage = function(e) {
    postMessage('Hello ' + e.data);
  };
`;

const worker = workerFromString(workerCode);

worker.onmessage = function(e) {
  console.log(e.data); // "Hello world"
};

worker.postMessage('world');

Multiple String Arguments

const imports = "importScripts('https://example.com/lib.js');";
const logic = "self.onmessage = function(e) { postMessage(process(e.data)); };";

const worker = workerFromString(imports, logic);

With TypeScript

import workerFromString from "@lopatnov/worker-from-string";

const worker = workerFromString(`
  self.onmessage = (e: MessageEvent) => {
    const result = e.data * 2;
    postMessage(result);
  };
`);

worker.onmessage = (e: MessageEvent) => {
  console.log('Result:', e.data);
};

worker.postMessage(21);

Demo

• Live Editor: https://lopatnov.github.io/worker-from-string/
• QUnit Tests: https://lopatnov.github.io/worker-from-string/test/index.html

Contributing

Contributions are welcome! Please read CONTRIBUTING.md before opening a pull request.

• Bug reports → open an issue
• Questions → Discussions
• Found it useful? A star on GitHub helps others discover the project

Built With

• TypeScript — strict typing throughout
• Rollup — bundled to ESM, CJS, and UMD formats
• QUnit — browser-based unit testing framework
• Blob API — in-memory worker script creation
• URL.createObjectURL — dynamic worker URL generation

License

Apache-2.0 © 2019–2026 Oleksandr Lopatnov · LinkedIn