Install

npm install @wasm-fmt/clang-format

npx jsr add @fmt/clang-format

Usage

CLI

This repository contains 3 executable files, namely clang-format, git-clang-format and clang-format-diff. For more information, please refer to https://clang.llvm.org/docs/ClangFormat.html

Node.js / Deno / Bun / Bundler

import { format } from "@wasm-fmt/clang-format";

const source = `
#include <iostream>
using namespace std;
auto main() -> int{
std::cout << "Hello World!" << std::endl;
return 0;}
`;

// JSON representation of Clang-Format Style Options
const config = JSON.stringify({
	BasedOnStyle: "Chromium",
	IndentWidth: 4,
	ColumnLimit: 80,
});

// or YAML representation of Clang-Format Style Options which is used in `.clang-format` file
const config2 = `---
BasedOnStyle: Chromium
IndentWidth: 4
ColumnLimit: 80

...
`;

// or the preset name
const config3 = "Chromium";

const formatted = format(source, "main.cc", config);

console.log(formatted);

The third argument of format is a Clang-Format Style Options, which can be one of the following:

1. A preset: LLVM, GNU, Google, Chromium, Microsoft, Mozilla, WebKit.
2. A YAML/JSON string representing the style options.
3. the string content of a .clang-format file.

See Clang-Format Style Options for more information.

Web

For web environments, you need to initialize WASM module manually:

import init, { format } from "@wasm-fmt/clang-format/web";

await init();

const source = `
#include <iostream>
using namespace std;
auto main() -> int{
std::cout << "Hello World!" << std::endl;
return 0;}
`;

const formatted = format(source, "main.cc", "Chromium");
console.log(formatted);

Vite

import init, { format } from "@wasm-fmt/clang-format/vite";

await init();
// ...

Entry Points

• . - Auto-detects environment (Node.js uses node, Webpack uses bundler, default is ESM)
• ./node - Node.js environment (no init required)
• ./esm - ESM environments like Deno (no init required)
• ./bundler - Bundlers like Webpack (no init required)
• ./web - Web browsers (requires manual init)
• ./vite - Vite bundler (requires manual init)

How does it work?

Clang-Format is a tool to format C/C++/Java/JavaScript/TypeScript/Objective-C/Protobuf/C# code.

This package is a WebAssembly build of Clang-Format, with a JavaScript wrapper.

Build from source

1. Install LLVM and Clang (version 18 or later).
2. Install CMake (version 3.27 or later).
3. Install Ninja (version 1.11 or later).
4. Install Emscripten (version 4.0.9).
5. Clone this repository.
6. Run scripts/build.sh.