While exporting a static array sometimes returns null

I have an array where I export it,
Sometimes this array returns me null, sometimes returns only the first element, sometimes all elements.

This is how I use

export const items= [
{
    title:"title1"
},
{
    title:"title2"
},
{
    title:"title3"
},

];

I use it in my app.js

import { items } from './data.js'

When I use it in useEffcet as I said, sometimes returns three elements some times just one element, and sometimes null. Thanks a lot

useEffet(() => {console.log(items)},[])