Function hasHandler

static/editor.md/lib/codemirror/lib/codemirror.js:7995–7998

(emitter, type)

  }

  function hasHandler(emitter, type) {
    var arr = emitter._handlers && emitter._handlers[type];
    return arr && arr.length > 0;
  }

  // Add on and off methods to a constructor's prototype, to make
  // registering events on such objects more convenient.