Node.js · Theory

Difference Between Returning a Callback and Just Calling a Callback in Node.js

Theory

650/723

Difference Between Returning a Callback and Just Calling a Callback in Node.js

Difference Between Returning a Callback and Just Calling a Callback is a Node.js topic. In plain words you use it for read notes.txt in a script. Don’t start with a slogan — start with that picture.

Smallest example: (err, data) => …. Type it, run it, and say what you see. If you can do that from memory, you know Difference Between Returning a Callback and Just Calling a Callback.

From the example next to this theory — Difference Between Returning a Callback and Just Calling a Callback in Node.

Trap — callback hell, no error-first. Fix that before you talk about advanced Node.js.

Viva: what is Difference Between Returning a Callback and Just Calling a Callback? Then show (err, data) => …. Then name the trap.

Exam tip

What is Difference Between Returning a Callback and Just Calling a Callback? Show this: (err, data) => …. Trap: callback hell, no error-first.

Example

function wait(ms) {
  return new Promise((resolve) => setTimeout(resolve, ms));
}

(async () => {
  console.log("start");
  await wait(50);
  console.log("done");
})();

Difference Between Returning a Callback and Just Calling a Callback in Node.js — async/await sits on Promises — cleaner than nested callbacks.

Short notes

DefDifference Between Returning a Callback and Just Calling a Callback — read notes.txt in a script.
Rule(err, data) => …
Trapcallback hell, no error-first
Usea script

Node.js · Theory

Difference Between Returning a Callback and Just Calling a Callback in Node.js

← All stacks

Theory

650/723

Difference Between Returning a Callback and Just Calling a Callback in Node.js

Smallest example: (err, data) => …. Type it, run it, and say what you see. If you can do that from memory, you know Difference Between Returning a Callback and Just Calling a Callback.

From the example next to this theory — Difference Between Returning a Callback and Just Calling a Callback in Node.

Trap — callback hell, no error-first. Fix that before you talk about advanced Node.js.

Viva: what is Difference Between Returning a Callback and Just Calling a Callback? Then show (err, data) => …. Then name the trap.

Exam tip

What is Difference Between Returning a Callback and Just Calling a Callback? Show this: (err, data) => …. Trap: callback hell, no error-first.

Example

function wait(ms) {
  return new Promise((resolve) => setTimeout(resolve, ms));
}

(async () => {
  console.log("start");
  await wait(50);
  console.log("done");
})();

Difference Between Returning a Callback and Just Calling a Callback in Node.js — async/await sits on Promises — cleaner than nested callbacks.

Short notes

DefDifference Between Returning a Callback and Just Calling a Callback — read notes.txt in a script.
Rule(err, data) => …
Trapcallback hell, no error-first
Usea script

Difference Between Returning a Callback and Just Calling a Callback in Node.js

Example

Short notes

Questions

Difference Between Returning a Callback and Just Calling a Callback in Node.js

Example

Short notes

Questions