Javascript module in nuxt [duplicate]

i am learning how to build a js module and upload to npm and install back into nuxt and try to use the function inside. trying to understand the proccess to build a module. but i keep getting error, i try to simple the module much as possible can anyone tell me what i miss out ?

module – dayuntilxmas
github enter link description here

dayuntilxmas

• README.md
• index.js
• package.json

index.js

export function greetPerson(name) {
    return `Hello ${name}`;
}

nuxt/pages/index.vue

<template>
    <div>
        <h1>this is plugins test framework</h1>
    </div>
</template>

<script>
    import {
        greetPerson
    } from 'dayuntilxmas'

    export default {
        data() {
            const greet = greetPerson()
            return {
                greet
            }
        },
        mounted() {
            console.log(this.greet('jade'))
        }
    }
</script>

so what do i missout ? i see some said need to include a html file inside module, but isit needed for some reason ?

the error it return was “Unexpected token ‘export'”