esbuild-plugin-polyfill-node

ESBuild plugin to polyfill Node.js built-ins and globals, geared towards edge environments and Deno (including Deno Deploy). It consists of two plugins: polyfillNode, which should work for most cases, and polyfillNodeForDeno which targets Deno and Deno Deploy specifically.

Installation

npm install esbuild-plugin-polyfill-node

polyfillNode

Usage

import { build } from "esbuild";
import { polyfillNode } from "esbuild-plugin-polyfill-node";

build({
	entryPoints: ["src/index.js"],
	bundle: true,
	outfile: "dist/bundle.js",
	plugins: [
		polyfillNode({
			// Options (optional)
		}),
	],
});

Options

• globals.buffer: Whether to inject the Buffer global. Disable it to prevent code like if (typeof Buffer !== "undefined") from pulling in the (quite large) buffer-es6 polyfill. Default: true.
• globals.process: Whether to inject the process global. Disable it to prevent process.env.NODE_ENV from pulling in the process-es6 polyfill. You can use the define option to replace process.env.NODE_ENV instead. Default: true.
• polyfills: Polyfills to inject. It's an object where the keys are the names of the polyfills and the values are false, true, or "empty". false disables the polyfill, true enables it, and "empty" injects an empty polyfill.

Implemented polyfills

Polyfills are provided by the @jspm/core package.

• _stream_duplex
• _stream_passthrough
• _stream_readable
• _stream_transform
• _stream_writable
• assert
• assert/strict
• async_hooks
• buffer
• child_process
• cluster
• console
• constants
• crypto
• dgram
• diagnostics_channel
• dns
• domain
• events
• fs
• fs/promises
• http
• http2
• https
• module
• net
• os
• path
• perf_hooks
• process
• punycode
• querystring
• readline
• repl
• stream
• string_decoder
• sys
• timers
• timers/promises
• tls
• tty
• url
• util
• v8
• vm
• wasi
• worker_threads
• zlib

¹ All except crypto and fs polyfills are on by default. crypto and fs have to be explicitly enabled. Otherwise, they will be replaced with empty stubs.

Globals

• global (aliased to globalThis)
• process¹ (imports the process module)
• Buffer¹ (imports the buffer module)
• __dirname (always "/")
• __filename (always "/index.js")

¹ process and Buffer shims can be disabled by passing globals.process: false and globals.buffer: false to the plugin options.

polyfillNodeForDeno

This plugin uses Deno's std/node library to polyfill Node builtins and globals.

Note that the std/node library has been removed from Deno in version 0.178.0 because now Deno has builtin support for Node builtin modules (e.g. node:fs). This plugin is still useful for deploying to Deno Deploy, which doesn't support them yet.

Usage

import { build } from "esbuild";
import { polyfillNodeForDeno } from "esbuild-plugin-polyfill-node";

build({
	entryPoints: ["src/index.js"],
	bundle: true,
	outfile: "dist/bundle.js",
	plugins: [
		polyfillNodeForDeno({
			// Options (optional)
		}),
	],
});

Options

• stdVersion: Version of the Deno standard library to use. Default: "0.177.0".
• globals: Whether to inject global polyfills (process, Buffer, setImmediate, clearImmediate, __dirname, and __filename). Default: true.
• polyfills: Polyfills to inject. It's an object where the keys are the names of the polyfills and the values are false, true, "npm" or "empty". false disables the polyfill, true enables it (default where exists), "npm" injects a polyfill from the NPM (default for "domain", "punycode", "vm", and "zlib"), and "empty" injects an empty polyfill (default for missing polyfills).

Credits

• Fatih Aygün, under the MIT license
• Loosely based on rollup-plugin-polyfill-node