It is possible to style console.log() output by utilising the
%c format specifier and passing a string of styles.
console.log('%ctest', 'font-size: 40px; color: red; text-transform: uppercase');
This can be useful for a number of things:
- Warning users against copying and pasting code into the console. Facebook currently log such a warning with some obvious styling.
- Making specific log messages stand out for debugging purposes.
- Companies used to leave job advert and easter egg comments hidden in HTML to target developers who were using view-source. In an age of minification, perhaps leaving these in the console could be a new approach!