Typescript: Property 'foo' does not exist on type 'Vue'.

Version

2.5.17

Reproduction link

https://stackblitz.com/edit/typescript-bc9ywj

Steps to reproduce

1. open index.ts, you will see:

1. change x: [String, Number, Array] to x: [String, Number], then errors disappear:

What is expected?

no typing errors.

What is actually happening?

typing errors exist.

[posva]

Check https://vuejs.org/v2/guide/typescript.html

---

Please, next time consider using the forum, the Discord server or StackOverflow for questions first. But feel free to come back and open an issue if it turns out to be a bug 🙂

[ITsolution-git]

export default Vue.extend({
    name: 'WebWhatsNew',
    data() {
        return {
            currentSlide: 0 as number
        };
    },
    methods: {
        nextSlide() {
            this.currentSlide += 1;
        },
    },
    computed: {
        internalOpen: {
            get(): boolean {
                return this.value;
            },
            set(val) {
                (this as any).$emit('input', false);
            },
        },
    },
});

I get this typing error with the code above.

When I remove

            set(val) {
                (this as any).$emit('input', false);
            },

then the compile error is gone.

Edit: I fixed the issue by set(val: boolean) , adding type to val.

It’s my mistake not to add type to val but the lint should give the proper error. However it fixes automatically when you try to fix the other typing issues.

Hope it helps anyone who hits the similar issue.