Blue number in Chrome Dev Console?

Question

In javascript I have a variable that I push to console.log then increment it and push it to the log again, which shows the below in the Chrome Dev Tools.

Answer 1

Note the difference between using commas and plus signs in console.log()

console.log( 'console.log("(" + 1 + ")"); // string concat' );
console.log("( " + 999 + " )"); 

console.log( 'console.log("(", 1, ")"); // string, number (blue), string' );
console.log("(", 999, ")");