Function modifyJSFunction

src/parseTools.mjs:864–902

(text, func)

// function, to which we pass the parsed-out arguments, body, and possible
// "async" prefix of the input function. Returns the output of that function.
export function modifyJSFunction(text, func) {
  // Match a function with a name.
  let async_;
  let args;
  let rest;
  let oneliner = false;
  let match = text.match(/^\s*(async\s+)?function\s+([^(]*)?\s*\(([^)]*)\)/);
  if (match) {
    async_ = match[1] ?? '';
    args = match[3];
    rest = text.slice(match[0].length);
  } else {
    // Match an arrow function
    let match = text.match(/^\s*(var (\w+) = )?(async\s+)?\(([^)]*)\)\s+=>\s+/);
    if (match) {
      async_ = match[3] ?? '';
      args = match[4];
      rest = text.slice(match[0].length);
      rest = rest.trim();
      oneliner = rest[0] != '{';
    } else {
      // Match a function without a name (we could probably use a single regex
      // for both, but it would be more complex).
      match = text.match(/^\s*(async\s+)?function\(([^)]*)\)/);
      assert(match, `could not match function:\n${text}\n`);
      async_ = match[1] ?? '';
      args = match[2];
      rest = text.slice(match[0].length);
    }
  }
  let body = rest;
  if (!oneliner) {
    const bodyStart = rest.indexOf('{');
    const bodyEnd = rest.lastIndexOf('}');
    assert(bodyEnd > 0);
    body = rest.substring(bodyStart + 1, bodyEnd);
  }
  return func(args, body, async_, oneliner);
}

export function runIfMainThread(text) {
  if (WASM_WORKERS || PTHREADS) {