Function eventsMixin

static/vuejs/vue.runtime.esm.js:1836–1930

(Vue)

}

function eventsMixin (Vue) {
  var hookRE = /^hook:/;
  Vue.prototype.$on = function (event, fn) {
    var this$1 = this;

    var vm = this;
    if (Array.isArray(event)) {
      for (var i = 0, l = event.length; i < l; i++) {
        this$1.$on(event[i], fn);
      }
    } else {
      (vm._events[event] || (vm._events[event] = [])).push(fn);
      // optimize hook:event cost by using a boolean flag marked at registration
      // instead of a hash lookup
      if (hookRE.test(event)) {
        vm._hasHookEvent = true;
      }
    }
    return vm
  };

  Vue.prototype.$once = function (event, fn) {
    var vm = this;
    function on () {
      vm.$off(event, on);
      fn.apply(vm, arguments);
    }
    on.fn = fn;
    vm.$on(event, on);
    return vm
  };

  Vue.prototype.$off = function (event, fn) {
    var this$1 = this;

    var vm = this;
    // all
    if (!arguments.length) {
      vm._events = Object.create(null);
      return vm
    }
    // array of events
    if (Array.isArray(event)) {
      for (var i$1 = 0, l = event.length; i$1 < l; i$1++) {
        this$1.$off(event[i$1], fn);
      }
      return vm
    }
    // specific event
    var cbs = vm._events[event];
    if (!cbs) {
      return vm
    }
    if (arguments.length === 1) {
      vm._events[event] = null;
      return vm
    }
    // specific handler