Node.js · Theory

forEach()

Theory

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forEach()

forEach() (function) sits in a first job task. Rohit’s job is a forEach function dry-run. Write that first.

forEach() (function) on the board: one forEach function step Rohit can write from memory. Then say what a forEach function dry-run looks like after.

Without forEach() (function), a first job task gets messy and a forEach function dry-run is hard to trust.

Rohit ships forEach() (function) in a first job task. That is the use case worth saying.

forEach() (function) trap — skipping the failure case for forEach function. Rohit loses marks for that every viva.

After forEach() (function), Rohit should still remember skipping the failure case for forEach function.

Viva for forEach() (function): what it is → one forEach function step Rohit can write from memory → the mistake (skipping the failure case for forEach function).

Exam tip

Say forEach() (function) in one breath, then one forEach function step Rohit can write from memory, then skipping the failure case for forEach function.

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) — Rohit uses it for a forEach function dry-run in a first job task.
RuleforEach() (function) → one forEach function step Rohit can write from memory.
RememberforEach() (function) + the event loop (a first job task).
UseforEach() (function) in a first job task (a forEach function dry-run).
TrapforEach() (function) — skipping the failure case for forEach function.
ExforEach() (function) → a forEach function dry-run.

// 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()

Example

Short notes

Questions

forEach()

Example

Short notes

Questions