in the case of non-ts, you can directly

import * as methods from "./index.js"

vue({
  methods:methods  
})

components, such as

index.js exported

helloworld();

components, you can directly

this.helloWorld()

it won"t work after using ts. What"s going on? can it be like a filter

Object.keys(filters).forEach(key => {
    Vue.filter(key, filters[key])
})