What does the [whatever]:[number] construct mean in the developer console?

Question

When I was using the developer console in the browser, I accidentally entered a construction like whatewer:42 The console in response output a number after the colon. I don't understand why such a construction is needed. If you use it anywhere else, you get an error.

Answer 1

If you use it anywhere else, you get an error.

No, you don't. It's a labeled statement.

function test() {
  whatever: 42;
  console.log('No error');
}

test();