function addHandler()

in web-ui/src/js/vue.js [5684:5734]

• 46 lines of code
• 20 McCabe index (conditional complexity)

function addHandler (
  el,
  name,
  value,
  modifiers,
  important,
  warn
) {
  // warn prevent and passive modifier
  /* istanbul ignore if */
  if (
    "development" !== 'production' && warn &&
    modifiers && modifiers.prevent && modifiers.passive
  ) {
    warn(
      'passive and prevent can\'t be used together. ' +
      'Passive handler can\'t prevent default event.'
    );
  }
  // check capture modifier
  if (modifiers && modifiers.capture) {
    delete modifiers.capture;
    name = '!' + name; // mark the event as captured
  }
  if (modifiers && modifiers.once) {
    delete modifiers.once;
    name = '~' + name; // mark the event as once
  }
  /* istanbul ignore if */
  if (modifiers && modifiers.passive) {
    delete modifiers.passive;
    name = '&' + name; // mark the event as passive
  }
  var events;
  if (modifiers && modifiers.native) {
    delete modifiers.native;
    events = el.nativeEvents || (el.nativeEvents = {});
  } else {
    events = el.events || (el.events = {});
  }
  var newHandler = { value: value, modifiers: modifiers };
  var handlers = events[name];
  /* istanbul ignore if */
  if (Array.isArray(handlers)) {
    important ? handlers.unshift(newHandler) : handlers.push(newHandler);
  } else if (handlers) {
    events[name] = important ? [newHandler, handlers] : [handlers, newHandler];
  } else {
    events[name] = newHandler;
  }
}