Intersection Observer — JS Technical Interview Questions & Answers

Detecting when an element enters the viewport.

Intersection Observer

  • Intersection Observer (js) is a JS topic. In plain words you use it for a short Intersection Observer js example in a script in the browser. Don’t start with a slogan — start with that picture.
  • Smallest example: the smallest Intersection Observer js example you can type. Type it, run it, and say what you see. If you can do that from memory, you know Intersection Observer (js).
  • From the example next to this theory: Detecting when an element enters the viewport.
  • Trap: only saying “Intersection Observer js” with no example. Fix that before you talk about advanced JS.
  • Viva: what is Intersection Observer (js)? Then show the smallest Intersection Observer js example you can type. Then name the trap.

Technical Interview Tip: What is Intersection Observer (js)? Show this: the smallest Intersection Observer js example you can type. Trap: only saying “Intersection Observer js” with no example.

Code Examples for Intersection Observer

Intersection Observer — working example

// Topic: Intersection Observer
const nums = [1, 2, 3];
const doubled = nums.map((n) => n * 2);
console.log(doubled);
console.log(doubled.reduce((a, b) => a + b, 0));

Intersection Observer: map then reduce on [1, 2, 3]. Say both prints.

How to Explain Intersection Observer to an Interviewer

What is Intersection Observer (js)?

Used for a short Intersection Observer js example a script in the browser Not just the heading

Give one small example of Intersection Observer (js).

the smallest Intersection Observer js example you can type Detecting when an element enters the viewport

What mistake do beginners make with Intersection Observer (js)?

only saying “Intersection Observer js” with no example Show the fix

Where do you use Intersection Observer (js)?

a script in the browser a short Intersection Observer js example