🔋 libems-mini

Runtime function-bits from emscripten for direct usage in javascript

About

This is a tiny module which brings a selection of javascript functions from the emscripten SDK to other WASM compilers – such as mainline clang.

Usage

// main.ts
import initEMS from 'libems-mini'

let module = initEMS({ instantiateWasm: async (imports, init) => {
  let wasm = await WebAssembly.instantiate('file.wasm', imports);
  return init(wasm.instance)
});

...

// example: ccall
let ptrAnswer = module.ccall('malloc', 'number', 'number', [42]);

// example: addFunction
let ptrJsFunc = module.addFunction(() => alert('hello from javascript!'), 'v');

Provided functions

• ccall
• addFunction
• removeFunction
• getValue
• setValue
• lengthBytesUTF8
• stringToUTF8
• stringToNewUTF8
• HEAP8
• HEAPU8
• HEAPU32

License info

libems-mini is licensed under the MIT License.

The module is entirely based on a selection of runtime functions that are part of the emscripten SDK (using emcc which is dual-licensed under MIT and the University of Illinois/NCSA Open Source License).

Created by Lesosoftware in 2025