undici-shim

undici-shim

A small ESM/UMD library providing the fast request function from Undici within Node, otherwise window.fetch is utilized when running in a browser environment.

Why?

Upon trying to distribute a project, I found Undici could not be used on the client-side.
As such, this is a drop-in replacement for Undici when using bundlers like webpack/rollup.

Without the overhead of WHATWG Streams, the request method proves much faster than fetch in both latency and throughput.

Tests	Samples	Results	Tolerance	Difference with slowest
undici - fetch	20	1028.31 req/sec	± 2.71 %	-
http - no keepalive	10	3891.51 req/sec	± 2.00 %	+ 278.44 %
undici - pipeline	95	6034.47 req/sec	± 2.95 %	+ 486.83 %
http - keepalive	50	6382.57 req/sec	± 2.98 %	+ 520.68 %
undici - request	15	8528.35 req/sec	± 2.11 %	+ 729.35 %

Install

npm i undici-shim

Usage

ESM

import request from 'undici-shim'
const res = await request('https://jsonplaceholder.typicode.com/posts/1')

console.log(await res.body.json())

You can also use Undici fetch instead of request for consistency across environments.

import { fetch } from 'undici-shim'
const res = await fetch('https://jsonplaceholder.typicode.com/posts/1')

console.log(await res.json())

CommonJS

const { fetch } = require('undici-shim')

fetch('https://jsonplaceholder.typicode.com/posts/1')
    .then(res => res.json())
    .then(console.log)

Named Exports

Node
Starting from v1.3.2, named exports are identical to Undici.

import { request, Dispatcher, Headers, ... } = from 'undici-shim'

Browser

import { fetch, Request, Response, Headers } = from 'undici-shim'