JSFiddle - React, Tailwind, and code Playground

JavaScript

const arr = [
	{
  	id: ''
  },
  {
  	id: ''
  },
  {
  	id: ''
  },
  {
  	id: ''
  },
  {
  	id: ''
  },
  {
  	id: ''
  },
  {
  	id: ''
  },
  {
  	id: ''
  },
  {
  	id: ''
  }
];

function setId() {
	const storage = window.localStorage;
	if(storage.getItem('data')) {
  
  	JSON.parse(storage.getItem('data')).map((el, i) => {
    	arr[i] = el.id;
    });
    
  } else {
  
  	const data = arr.map(el => {
      el.id = Math.random().toString();
      return el;
    });

    storage.setItem('data', JSON.stringify(data));
    
  }
  
  console.log(arr);
  
  return;
  
}

setId();