What’s the use case of the JS console? code example

Example: what is console in javascript

var str = "Howdy GeeksforGeeks"
var geek = {
  book: "harrypotter",
  price: "2000"
};
var geek2 = [10, 20, 30];
console.log(str);
console.dir(str);
console.dir(geek);
console.log("geek (log) = ", geek);
console.dir(geek2);
console.log("geek2 (log) = ", geek2);

// Prints only string as dir() takes 
// only one parameter. 
console.dir("geek2 (dir) = ", geek2);