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@rsbuild/plugin-node-polyfill

An Rsbuild plugin to automatically inject polyfills for Node.js builtin modules into the browser side.

When to use

Normally, we don't need to use Node builtin modules on the browser side. However, it is possible to use some Node builtin modules when the code will run on both the Node side and the browser side, and this plugin provides browser versions of polyfills for these Node builtin modules.

By using the Node Polyfill plugin, polyfills for Node builtin modules are automatically injected into the browser-side, allowing you to use these modules on the browser side with confidence.

Usage

Install:

npm add @rsbuild/plugin-node-polyfill -D

Add plugin to your rsbuild.config.ts:

// rsbuild.config.ts
import { pluginNodePolyfill } from "@rsbuild/plugin-node-polyfill";

export default {
  plugins: [pluginNodePolyfill()],
};

Node Polyfills

Globals

• Buffer
• process

When you use the above global variables in your code, the corresponding polyfill will be automatically injected.

For instance, the following code would inject the Buffer polyfill:

const bufferData = Buffer.from("abc");

You can disable this behavior through the globals option of the plugin:

pluginNodePolyfill({
  globals: {
    Buffer: false,
    process: false,
  },
});

Modules

• assert
• buffer
• console
• constants
• crypto
• domain
• events
• http
• https
• os
• path
• punycode
• process
• querystring
• stream
• _stream_duplex
• _stream_passthrough
• _stream_readable
• _stream_transform
• _stream_writable
• string_decoder
• sys
• timers
• tty
• url
• util
• vm
• zlib

When the above module is referenced in code via import / require syntax, the corresponding polyfill will be injected.

import { Buffer } from "buffer";

const bufferData = Buffer.from("abc");

Fallbacks

• child_process
• cluster
• dgram
• dns
• fs
• module
• net
• readline
• repl
• tls

Currently there is no polyfill for the above modules on the browser side, so when you import the above modules, it will automatically fallback to an empty object.

import fs from "fs";

console.log(fs); // -> {}

Options

globals

Used to specify whether to inject polyfills for global variables.

• Type:

type Globals = {
  process?: boolean;
  Buffer?: boolean;
};

• Default:

const defaultGlobals = {
  Buffer: true,
  process: true,
};

protocolImports

Whether to polyfill Node.js builtin modules starting with node:.

• Type: boolean
• Default: true

For example, if you disable protocolImports, modules such as node:path, node:http, etc. will not be polyfilled.

pluginNodePolyfill({
  protocolImports: false,
});

License

MIT.