nwjs/nw.js · error · TypeError

'failed' must be a valid function.

Error message

'failed' must be a valid function.

What it means

Thrown by the nw.Shortcut constructor when the 'failed' option is present but is not a function. 'failed' is the callback invoked when the accelerator cannot be registered (e.g. the key combo is taken by the OS), so it must be callable.

Source

Thrown at src/api/shortcut/shorcut.js:42

  if (typeof option != 'object')
    throw new TypeError('Invalid option.');

  if (!option.hasOwnProperty('key'))
    throw new TypeError("Shortcut requires 'key' to specify key combinations.");

  option.key = String(option.key);
  this.key = option.key;

  if (option.hasOwnProperty('active')) {
    if (typeof option.active != 'function')
      throw new TypeError("'active' must be a valid function.");
    else
      this.active = option.active;
  }

  if (option.hasOwnProperty('failed')) {
    if (typeof option.failed != 'function')
      throw new TypeError("'failed' must be a valid function.");
    else
      this.failed = option.failed;
  }

  v8_util.setHiddenValue(this, 'option', option);
  nw.allocateObject(this, option);
}

require('util').inherits(Shortcut, exports.Base);

Shortcut.prototype.handleEvent = function(ev) {
  if (ev == 'active') {
    if (typeof this.active == 'function')
      this.active();
  } else if (ev == 'failed') {
    if (typeof this.failed == 'function')
      this.failed(arguments[1]);
  }

View on GitHub (pinned to e15da848e9)

Solutions

1. Provide a real function for 'failed' or omit it entirely.
2. Guard with typeof before passing: `if (typeof cb === 'function') opt.failed = cb;`.

Example fix

// before
new nw.Shortcut({ key: 'Ctrl+A', failed: false });
// after
new nw.Shortcut({ key: 'Ctrl+A', failed: (err) => console.error(err) });

if (option && option.hasOwnProperty('failed') && typeof option.failed !== 'function') {
  throw new Error('option.failed must be a function');
}

function isCallable(v) { return typeof v === 'function'; }

try { new nw.Shortcut(opt); } catch (e) { if (/failed/.test(e.message)) logger.warn(e.message); else throw e; }

When it happens

Trigger: Calling `new nw.Shortcut({ key: 'Ctrl+A', failed: null })`, `failed: false`, or `failed: someObj.method` where `this` binding produced undefined.

Common situations: Copy-paste from a config that set failed to a boolean flag; passing a value from an optional field that defaulted to a non-function.

Related errors

• 'active' must be a valid function.
• Invalid option.
• Shortcut requires 'key' to specify key combinations.
• Invalid option
• 'click' must be a valid Function

AI-assisted analysis of nwjs/nw.js@e15da848e9 (2026-08-13). Data as JSON: /api/errors/3fe4cd20b85806fb. Report an issue: GitHub.