12 Ways to Improve Your DevTools Console Logging

[Costas]

Log messages can be styled using standard CSS passed as a string in a second parameter of any message type. A %c marker in the message indicates where the styling will be applied, e.g.

console.log(
  '%cOK, things are really bad now!',
  `
  font-size: 2em;
  padding: 0.5em 2em;
  margin: 1em 0;
  color: yellow;
  background-color: red;
  border-radius: 50%;
  `
);

https://blog.asayer.io/12-ways-to-improve-your-devtools-console-logging