I tried solution suggested here How to get the console.log content as string in JavaScript

Problem is it's missing the full formatted output : it gives a, b, c instead whereas I'd like to get ["a", "b", "c"] for my case https://jsfiddle.net/eywjn9o8/

var logBackup = console.log;
var logMessages = [];

console.log = function() {
    logMessages.push.apply(logMessages, arguments);
    logBackup.apply(console, arguments);
};

const object1 = {
  a: 'somestring',
  b: 42,
  c: false
};

console.log(Object.keys(object1));
alert(logMessages)