JSFiddle - React, Tailwind, and code Playground

JavaScript

var jsonres = {
    "key01": [10, "Key01 Description"],
    "key02": [false, "It's a false value"],
    "key03": [null, "Testing Null"],
    "key04": ["tests", "Another Test Value"],
    "key05": [[25, 50], "Some testing values"]
}

for(var key in jsonres){
   if(jsonres.hasOwnProperty(key)){
      jsonres[key] = jsonres[key][0];
   }
}

console.log(jsonres)