Fastjs

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Quick Start ​

Fastjs supports several ways to be loaded — pick the one that fits your project.

With Bundler Recommended ​

Am I using a bundler?

Common bundlers include vite, webpack, rollup, and esbuild-based tools.

Why is the bundler build recommended?

The bundler build keeps process.env.NODE_ENV checks in place, so your bundler can dead-code-eliminate the development-only warnings in production. It is also fully tree-shakeable.

The bundler build keeps your final bundle small and lets you import only the helpers you need.

Create a new project ​

Fastjs CLI is archived

The official create-fastjs CLI was archived on Dec 22, 2023 and is no longer maintained. Use Vite (below) to scaffold a project and add jsfast manually.

Fastjs works great with vite:

bash
npm create vite@latest fastjs-project
bash
yarn create vite@latest fastjs-project
bash
pnpm create vite@latest fastjs-project
bash
bun create vite@latest fastjs-project

Install Fastjs ​

bash
cd fastjs-project
npm i jsfast
bash
cd fastjs-project
yarn add jsfast
bash
cd fastjs-project
pnpm add jsfast
bash
cd fastjs-project
bun add jsfast

Usage ​

Open src/main.js and try the example:

js
import { date } from "jsfast";

console.log(date.string()); // e.g. "2025-06-19 09:32:14"

A couple more one-liners to taste what's available:

js
import { dom, request, cookie, rand, uuid } from "jsfast";

dom("body").addClass("ready").text("Hello Fastjs!");
request.get("/api/posts").then((data) => console.log(data));
cookie.set("token", "abc", { maxAge: 3600, sameSite: "Lax" });
console.log(rand(0, 9), uuid());

With CDN ​

Drop a single <script> to expose the fastjs global.

Usage ​

html
<script src="https://cdn.jsdelivr.net/npm/jsfast/dist/fastjs.global.js"></script>
<!-- or -->
<script src="https://unpkg.com/jsfast/dist/fastjs.global.js"></script>
js
console.log(fastjs.date.string());
fastjs.dom("body").text("Hello!");

Prefer to skip the namespace:

js
const { date, dom, cookie } = fastjs;

For production, use the minified, development-stripped build:

html
<script src="https://cdn.jsdelivr.net/npm/jsfast/dist/fastjs.global.prod.js"></script>

With Node.js ​

Production environment

Fastjs ships separate development and production builds. The production build automatically kicks in when NODE_ENV === "production". Check the variable if you do not see the speed/size you expect.

Fastjs requires Node.js ≥ 18 (for the global fetch, AbortController, and AbortSignal.timeout).

Install ​

bash
npm i jsfast

Usage ​

js
// ESM
import { date, request, uuid } from "jsfast";

// CJS
const { date, request, uuid } = require("jsfast");

console.log(date.string(), uuid());

The browser-only modules (dom, cookie, utils.copy) degrade safely in Node — reads return null / false, writes are no-ops and a warning is logged in development mode.

With Direct Import ​

Use the native ESM build directly in the browser, no bundler required.

Usage ​

html
<script type="module">
  import { date } from "https://cdn.jsdelivr.net/npm/jsfast/dist/fastjs.esm-browser.js";
  // or production:
  // import { date } from "https://cdn.jsdelivr.net/npm/jsfast/dist/fastjs.esm-browser.prod.js";

  console.log(date.string());
</script>