Node.js: Asynchronous Callback Execution. Is this Zalgo?

Question

Executing the below using node - 6.0.

function A(callback) {
  console.log(\'A\');
  callback();
}

function B() {
  console.log(\'B\')
}

f         


        

Answer 1

No, neither of these is zalgo. Your first A function always calls its callback synchronously, and should be documented as such. Your second A function always calls its callback asynchronously, and should be documented as such. Nothing is wrong with that, we use thousands of these every day. The outputs A C B and A B C are deterministic.

Zalgo refers to the uncertainty whether a callback is asynchronous or not.

function A(callback) {
  console.log('A');
  if (Math.random() < 0.5) {
    callback();
  } else {
    process.nextTick(callback);
  }
}

The output of the invocation A(C); B(); would be totally unpredictable.