`vm.$off` not working when passing an array as first argument

[cheng-kang]

Version

2.5.2

Reproduction link

https://jsfiddle.net/CHENGKANG/4owjvLLk/5/

Steps to reproduce

1. Add multiple custom event listeners

this.$on(['event1', 'event2'], () => {
    console.log('This is callback.')
})

2. Try to remove them with vm.$off

this.$off(['event1', 'event2'])

3. Try to emit the removed events

this.$emit('event1')

What is expected?

Nothing should happen because the event listeners should have been removed.

What is actually happening?

Got "This is callback." printed in the console, which means that the event listeners are not removed as expected.

---

Please check my post in Vue forum for more details.

[cheng-kang]

Changing the condition for specific event from arguments.length === 1 to !fn should do.

  // Fixed Version
  Vue.prototype.$off = function (event?: string | Array<string>, fn?: Function): Component {
    const vm: Component = this
    // all
    if (!arguments.length) {
      vm._events = Object.create(null)
      return vm
    }
    // array of events
    if (Array.isArray(event)) {
      for (let i = 0, l = event.length; i < l; i++) {
        this.$off(event[i], fn)
      }
      return vm
    }
    // specific event
    const cbs = vm._events[event]
    if (!cbs) {
      return vm
    }
    if (!fn) {
      vm._events[event] = null
      return vm
    }

    // specific handler
    let cb
    let i = cbs.length
    while (i--) {
      cb = cbs[i]
      if (cb === fn || cb.fn === fn) {
        cbs.splice(i, 1)
        break
      }
    }
    return vm
  }

  // Current Version
  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 = 0, l = event.length; i < l; i++) {
        this$1.$off(event[i], fn);
      }
      return vm
    }
    // specific event
    var cbs = vm._events[event];
    if (!cbs) {
      return vm
    }
    if (arguments.length === 1) {
      vm._events[event] = null;
      return vm
    }
    if (fn) {
      // specific handler
      var cb;
      var i$1 = cbs.length;
      while (i$1--) {
        cb = cbs[i$1];
        if (cb === fn || cb.fn === fn) {
          cbs.splice(i$1, 1);
          break
        }
      }
    }
    return vm
  };

[madskonradsen]

Thanks to the nice description and analysis by @cheng-kang , I have just submitted #6949 with a passing test.

[yyx990803]

closed via c24f3e4