Node.js · Theory

forEach()

Theory

170/723

forEach()

forEach() (function) is a Node.js topic. In plain words you use it for a short forEach function example in a script or API on localhost. Don’t start with a slogan — start with that picture.

Smallest example: the smallest forEach function example you can type. Type it, run it, and say what you see. If you can do that from memory, you know forEach() (function).

From the example next to this theory — forEach(): find user 2, then list names.

Trap — only saying “forEach function” with no example. Fix that before you talk about advanced Node.js.

Viva — what is forEach() (function)? Then show the smallest forEach function example you can type. Then name the trap.

Exam tip

What is forEach() (function)? Show this: the smallest forEach function example you can type. Trap: only saying “forEach function” with no example.

Example

// forEach()
const users = [
  { id: 1, name: "Asha" },
  { id: 2, name: "Ravi" },
];

function findUser(id) {
  return users.find((u) => u.id === id) ?? null;
}

console.log(findUser(2));
console.log(users.map((u) => u.name));

forEach(): find user 2, then list names. Say both prints.

Short notes

DefforEach() (function) — a short forEach function example in a script or API on localhost.
Rulethe smallest forEach function example you can type
Traponly saying “forEach function” with no example
Usea script or API on localhost

Node.js · Theory

forEach()

← All stacks

Theory

170/723

forEach()

forEach() (function) is a Node.js topic. In plain words you use it for a short forEach function example in a script or API on localhost. Don’t start with a slogan — start with that picture.

Smallest example: the smallest forEach function example you can type. Type it, run it, and say what you see. If you can do that from memory, you know forEach() (function).

From the example next to this theory — forEach(): find user 2, then list names.

Trap — only saying “forEach function” with no example. Fix that before you talk about advanced Node.js.

Viva — what is forEach() (function)? Then show the smallest forEach function example you can type. Then name the trap.

Exam tip

What is forEach() (function)? Show this: the smallest forEach function example you can type. Trap: only saying “forEach function” with no example.

Example

// forEach()
const users = [
  { id: 1, name: "Asha" },
  { id: 2, name: "Ravi" },
];

function findUser(id) {
  return users.find((u) => u.id === id) ?? null;
}

console.log(findUser(2));
console.log(users.map((u) => u.name));

forEach(): find user 2, then list names. Say both prints.

Short notes

DefforEach() (function) — a short forEach function example in a script or API on localhost.
Rulethe smallest forEach function example you can type
Traponly saying “forEach function” with no example
Usea script or API on localhost

forEach()

Example

Short notes

Questions

forEach()

Example

Short notes

Questions