The console.count() method logs the number of times that this particular call to count() has been called.

label Optional

A string. If supplied, count() outputs the number of times it has been called with that label. If omitted, count() behaves as though it was called with the "default" label.

None (undefined).

For example, given code like this:

let user = "";

function greet() {
  console.count();
  return `hi ${user}`;
}

user = "bob";
greet();
user = "alice";
greet();
greet();
console.count();

Console output will look something like this:

"default: 1"
"default: 2"
"default: 3"
"default: 4"

The label is displayed as default because no explicit label was supplied.

If we pass the user variable as the label argument to the first invocation of count(), and the string "alice" to the second:

let user = "";

function greet() {
  console.count(user);
  return `hi ${user}`;
}

user = "bob";
greet();
user = "alice";
greet();
greet();
console.count("alice");

We will see output like this:

"bob: 1"
"alice: 1"
"alice: 2"
"alice: 3"

We're now maintaining separate counts based only on the value of label.