lightningTable.js

import { LightningElement } from 'lwc';
//import the helper javascript module/file
import fetchDataHelper from './fetchDataHelper';

const columns = [
    { label: 'Label', fieldName: 'name' },
    { label: 'Website', fieldName: 'website', type: 'url' },
    { label: 'Phone', fieldName: 'phone', type: 'phone' },
    { label: 'Balance', fieldName: 'amount', type: 'currency' },
    { label: 'CloseAt', fieldName: 'closeAt', type: 'date' },
];

export default class LightningTable extends LightningElement {

    data = [];
    columns = columns;
    
    // async-await method 
    async connectedCallback() {
        const data = await fetchDataHelper({ amountOfRecords: 100 });
        this.data = data;
    }
}