esbuild-plugins-node-modules-polyfill

Polyfills nodejs builtin modules for the browser.

Description

Polyfills nodejs builtin modules and globals for the browser.

Features

• Written In Typescript
• Offers CJS and ESM builds
• Full TypeScript & JavaScript support
• Supports node: protocol
• Supports browser field in package.json
• Optionally injects globals
• Optionally provides empty fallbacks
• Supports custom polyfill overrides

Install

npm install --save-dev esbuild-plugins-node-modules-polyfill

Usage

import { nodeModulesPolyfillPlugin } from 'esbuild-plugins-node-modules-polyfill';
import { build } from 'esbuild';
build({
	plugins: [nodeModulesPolyfillPlugin()],
});

Inject globals when detected:

import { nodeModulesPolyfillPlugin } from 'esbuild-plugins-node-modules-polyfill';
import { build } from 'esbuild';
build({
	plugins: [
		nodeModulesPolyfillPlugin({
			globals: {
				process: true,
				Buffer: true,
			},
		}),
	],
});

Note

If you are utilizing the modules option, ensure that you include polyfills for the global modules you are using.

Configure which modules to polyfill:

import { nodeModulesPolyfillPlugin } from 'esbuild-plugins-node-modules-polyfill';
import { build } from 'esbuild';
build({
	plugins: [
		nodeModulesPolyfillPlugin({
			modules: ['crypto'],
		}),
	],
});

import { nodeModulesPolyfillPlugin } from 'esbuild-plugins-node-modules-polyfill';
import { build } from 'esbuild';
build({
	plugins: [
		nodeModulesPolyfillPlugin({
			modules: {
				crypto: true,
				fs: false,
			},
		}),
	],
});

Override polyfills with custom implementations:

You can provide custom polyfill implementations for specific modules. This is useful when you need to customize the behavior of a polyfill for your specific use case.

import { nodeModulesPolyfillPlugin } from 'esbuild-plugins-node-modules-polyfill';
import { build } from 'esbuild';
build({
	plugins: [
		nodeModulesPolyfillPlugin({
			overrides: {
				process: './my-custom-process-polyfill.js',
			},
		}),
	],
});

The custom polyfill file should export a default export with your implementation:

// my-custom-process-polyfill.js
const customProcess = {
	env: {},
	version: 'v1.0.0',
	platform: 'browser',
	stdout: {
		write: (data) => console.log(data),
	},
	// ... other process properties
};

export default customProcess;

Note

Custom overrides work with both process and node:process style imports. You can specify the override with or without the node: prefix.

Important

• File paths should be absolute paths or relative to the project root (where esbuild is executed), not relative to the configuration file. This is important because esbuild will resolve these paths, and relative paths might not work as expected if you run the build command from a different directory.
• If a module is specified in both overrides and modules options (e.g., overrides: { process: './custom.js' } and modules: { process: 'empty' }), the override takes precedence and the modules configuration for that module will be ignored.

Provide empty polyfills:

Provide empty polyfills for specific modules:

import { nodeModulesPolyfillPlugin } from 'esbuild-plugins-node-modules-polyfill';
import { build } from 'esbuild';
build({
	plugins: [
		nodeModulesPolyfillPlugin({
			modules: {
				fs: 'empty',
				crypto: true,
			},
		}),
	],
});

Provide empty fallbacks for any unpolyfilled modules:

import { nodeModulesPolyfillPlugin } from 'esbuild-plugins-node-modules-polyfill';
import { build } from 'esbuild';
build({
	plugins: [
		nodeModulesPolyfillPlugin({
			fallback: 'empty',
		}),
	],
});

Provide empty fallbacks for any unconfigured modules:

import { nodeModulesPolyfillPlugin } from 'esbuild-plugins-node-modules-polyfill';
import { build } from 'esbuild';
build({
	plugins: [
		nodeModulesPolyfillPlugin({
			fallback: 'empty',
			modules: {
				crypto: true,
			},
		}),
	],
});

Fail the build when certain modules are used:

Important

The write option in esbuild must be false to support this.

import { nodeModulesPolyfillPlugin } from 'esbuild-plugins-node-modules-polyfill';
import { build } from 'esbuild';
const buildResult = await build({
	write: false,
	plugins: [
		nodeModulesPolyfillPlugin({
			modules: {
				crypto: 'error',
				path: true,
			},
		}),
	],
});

Fail the build when a module is not polyfilled or configured:

Important

The write option in esbuild must be false to support this.

import { nodeModulesPolyfillPlugin } from 'esbuild-plugins-node-modules-polyfill';
import { build } from 'esbuild';
const buildResult = await build({
	write: false,
	plugins: [
		nodeModulesPolyfillPlugin({
			fallback: 'error',
			modules: {
				path: true,
			},
		}),
	],
});

Provide a custom error formatter when a module is not polyfilled or configured:

Return an esbuild PartialMessage object from the formatError function to override any properties of the default error message.

Important

The write option in esbuild must be false to support this.

import { nodeModulesPolyfillPlugin } from 'esbuild-plugins-node-modules-polyfill';
import { build } from 'esbuild';
const buildResult = await build({
	write: false,
	plugins: [
		nodeModulesPolyfillPlugin({
			fallback: 'error',
			modules: {
				path: true,
			},
			formatError({ moduleName, importer, polyfillExists }) {
				return {
					text: polyfillExists
						? `Polyfill has not been configured for "${moduleName}", imported by "${importer}"`
						: `Polyfill does not exist for "${moduleName}", imported by "${importer}"`,
				};
			},
		}),
	],
});

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Contributors ✨

Thanks goes to these wonderful people: