Can callbacks be synchronous?

Synchronous callback

Yes, callbacks can be synchronous

const gods = ['Apollo', 'Artemis', 'Ares', 'Zeus'];

gods.forEach(function (eachName, index) {
  console.log(index + '. ' + eachName);
});

In this example given above we loop through an array of Greek gods and print the index numbers and values to the console. The expected parameter of forEach() is a callback function, which itself takes two parameters, a reference to the array name and index values. However, it doesn't wait for anything it runs immediately.