Change directive definition for vue 3.

vue-directive-clickOutside.js

const events = ['click'];

function onClickOutside({ event, el, handler, middleware }) {
  const isClickOutside =
    event.target !== el
    && !el.contains(event.target);

  if (!isClickOutside || !middleware(event, el)) {
    return null;
  }

  return handler(event, el);
}

const instances = new Map();

//Requires loop to toggle events for several listeners of an element
function toggleEventListeners(eventHandlers) {
  return (action) => {
    eventHandlers.forEach(({ event, handler }) => {
      document[`${action}EventListener`](event, handler, true);
    })
  }
}

//Validator function
function processArgs(value) {
  const isFunction = typeof value === 'function';

  if (!isFunction && typeof value !== 'object') {
      throw new Error(`v-click-outside: Binding value should be a function or an object, ${typeof bindingValue} given`)
  }

  return {
    handler: isFunction ? value : value.handler,
    middleware: value.middleware || (() => true),
  }
}

//Now need adapter to handle several events for one Map element
function eventAdapter(events, { el, handler, middleware }) {
  return events.map((eventName) => ({
    event: eventName,
    handler: (event) => onClickOutside({ event, el, handler, middleware })
  }));
}

function bind(el, { value }) {
  const { handler, middleware } = processArgs(value);
  const eventHandlers = eventAdapter(events, { el, handler, middleware });

  instances.set(
    el,
    eventHandlers,
  );

  toggleEventListeners(eventHandlers)('add');
}

function unbind(el) {
  const eventHandlers = instances.get(el);

  toggleEventListeners(eventHandlers)('remove');

  instances.delete(el);
}

const directive = {
  beforeMount:bind,
  unmounted:unbind,
};

export default directive;

#Setting global custom directive in Vue 3.

import clickOutside from './directive/vue-directive-clickOutside'

createApp(App).directive('click-outside', clickOutside)