Node.js · Theory

console.error()

Theory

73/723

console.error()

console.error() (function) is a Node.js topic. In plain words you use it for console.log marks in a script. Don’t start with a slogan — start with that picture.

Smallest example: console.log / error / table. Type it, run it, and say what you see. If you can do that from memory, you know console.error() (function).

From the example next to this theory — console.error(): find user 2, then list names. Say both prints..

Trap — console.log in a hot loop in production. Fix that before you talk about advanced Node.js.

Viva — what is console.error() (function)? Then show console.log / error / table. Then name the trap.

Exam tip

What is console.error() (function)? Show this: console.log / error / table. Trap: console.log in a hot loop in production.

Example

// console.error()
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));

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

Short notes

Defconsole.error() (function) — console.log marks in a script.
Ruleconsole.log / error / table
Trapconsole.log in a hot loop in production
Usea script

Node.js · Theory

console.error()

← All stacks

Theory

73/723

console.error()

console.error() (function) is a Node.js topic. In plain words you use it for console.log marks in a script. Don’t start with a slogan — start with that picture.

Smallest example: console.log / error / table. Type it, run it, and say what you see. If you can do that from memory, you know console.error() (function).

From the example next to this theory — console.error(): find user 2, then list names. Say both prints..

Trap — console.log in a hot loop in production. Fix that before you talk about advanced Node.js.

Viva — what is console.error() (function)? Then show console.log / error / table. Then name the trap.

Exam tip

What is console.error() (function)? Show this: console.log / error / table. Trap: console.log in a hot loop in production.

Example

// console.error()
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));

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

Short notes

Defconsole.error() (function) — console.log marks in a script.
Ruleconsole.log / error / table
Trapconsole.log in a hot loop in production
Usea script

console.error()

Example

Short notes

Questions

console.error()

Example

Short notes

Questions