walt-compiler/src/emitter/preamble.js

Alternative syntax for WebAssembly text format

// @flow
import { u32 } from 'wasm-types';
import OutputStream from '../utils/output-stream';

export const VERSION_1 = 0x1;
export const MAGIC = 0x6d736100;
export const MAGIC_INDEX = 0;
export const VERSION_INDEX = 4;

export default function write(version: number) {
  return new OutputStream()
    .push(u32, MAGIC, '\\0asm')
    .push(u32, version, `version ${version}`);
}