JSFiddle - React, Tailwind, and code Playground

JavaScript

localStorage.setItem('r1','true');
localStorage.setItem('k2','true');
localStorage.setItem('l3','true');
localStorage.setItem('r4','true');

var archive = [],
  keys = Object.keys(localStorage),
  i = 0, key;
  
for(; key=keys[i]; i++){
  if(key.charAt(0) === "r"){
  	archive.push(key + '=' + localStorage.getItem(key));
  }
}

console.log(archive);