Unicode naming for methods seems unsupported. Some warning will be appreciated.

[nobodxbodon]

Version

2.5.2

Reproduction link

https://jsfiddle.net/p48cLbe3/2/

Steps to reproduce

    <script src="https://unpkg.com/vue"></script>
    <div id="元素id5">
      <p>{{ 问好 }}</p>
      <button v-on:click="改口">改口</button>
    </div>

var 应用5 = new Vue({
  el: '#元素id5',
  data: {
    问好: '你好'
  },
  methods: {
    改口: function () {
      this.问好 = '吃了么'
    }
  }
})

What is expected?

Excuse me if this is closer to feature request.

It'll be great if method can support unicode naming. Otherwise it may be better to provide some feedback.

Thanks for your efforts.

What is actually happening?

I'm guessing validation passes because the method does exist, but somehow invoking method fails.

[javoski]

You can try

<button @click="改口()"></button>

if you really want this.

[nobodxbodon]

@javoski thanks. As I'm new to Vue, may I ask what's the difference between these two ways?

[posva]

It's just a workaround
by default Vue will call the method passing $event to it if you pass the function instead of calling it: @click="doIt" -> @click="doIt($event)"

[HerringtonDarkholme]

I don't think we can afford warning in runtime build, though :/

https://stackoverflow.com/a/9392578/2198656

if you were to summarize all these (variable naming) rules in a single ASCII-only regular expression for JavaScript, it would be 11,236 characters long (for ECMAScript 5.1 / Unicode 6.1.0)

[nobodxbodon]

As the alternative method suggested above does work, it just occurred to me that v-on:click="改口()" might work, and as I just tried it does work! While v-on:click="改口" doesn't.

[9percent]

By tracking the click event, it looks like Vue does treat the Unicode names differently behind the scene, while the method name is like "doIt", button click invokes the "boundFn" directly, but when the method name is an Unicode name, the button invokes something like a "click event handler" instead:

on: {
    "click": function($event) {
        改口
    }
}

[yyx990803]

In order to use the method name directly (shorthand) it needs to be a alphanumeric identifier. Any expression that is not an alphanumeric identifier is treated as a function body instead, which is why in this case () is needed. Adding shorthand support for full unicode, as @HerringtonDarkholme has pointed out, is too expensive and not worth it.

[nobodxbodon]

Thanks for addressing this. Still, I wonder if some feedback could be provided in this case, maybe something like "You used a non-alphanumeric identifier. If it's intended, add () as a workaround."?

[yyx990803]

The problem it's too expensive to detect "a non-alphanumeric identifier (maybe a unicode identifier)" from "a full expression"

[nobodxbodon]

Excuse me if I miss something obvious. I realize it's too expensive to decide if an identifier is legit unicode identifier, as pointed out above. However I thought detecting if an identifier is non-alphanumeric is easier, like checking if it matches /[A-Za-z_$][\w$]*/. That would require developer to check if it's legit unicode identifier, but having some feedback would be better than none, I suppose?
Anyways, as unicode naming is not at all in wide use, plus it does have alternative solution(with ()), thanks to the community support, I'd totally understand if this edge case has too low priority to be picked up in any time soon.
Thanks again for your patience and time!