Question 1

Wire Up Debounced Resize and Throttled Scroll Handlers on a Real Component

Accepted Answer

**Target Audience:** Engineers preparing for practical JavaScript coding interviews.
**Difficulty:** Medium

> **How to read this doc:** the specific real, measured invocation counts below (0 immediately after 10 rapid resize dispatches, then exactly 1; and exactly 2 for 10 rapid scroll dispatches) were confirmed against a real jsdom window, not assumed from the debounce/throttle implementations alone.

## 1. The problem, restated

Attach a debounced `resize` handler and a throttled `scroll` han

Question 2

Implement throttle(func, wait, {leading, trailing})

Accepted Answer

**Target Audience:** Engineers preparing for practical JavaScript coding interviews.
**Difficulty:** Medium

> **How to read this doc:** the key distinguishing claim from debounce — that throttle keeps firing at a steady rate DURING continuous activity rather than waiting for it to stop — was verified directly with a real, sustained 260ms burst of calls every 20ms.

## 1. The problem, restated

`throttle(fn, wait, options)` returns a wrapped function guaranteeing `fn` is invoked at most once per

Question 3

Implement debounce() with leading/trailing and cancel/flush

Accepted Answer

**Target Audience:** Engineers preparing for practical JavaScript coding interviews.
**Difficulty:** Medium

> **How to read this doc:** all 5 real behavior modes below — trailing-only, leading-only, cancel, flush, and leading+trailing together — were verified directly with real, timed `setTimeout`-based tests, not just reasoned about from the code.

## 1. The problem, restated

`debounce(fn, wait, options)` returns a wrapped function that delays calling `fn` until `wait` ms of silence have pass

Question 4

Debounce async promise resolver

Accepted Answer

**Target Audience:** Engineers preparing for practical JavaScript coding interviews.
**Difficulty:** Medium

> **How to read this doc:** the "every pending caller resolves, not just the last one" requirement — the part a plain callback-based debounce cannot handle at all — was verified directly: 3 real calls in a burst, all 3 returned promises resolving to the identical final result.

## 1. The problem, restated

`debounceAsync(fn, wait)` wraps an async function: only the LAST call in a rapid bu

Question 5

Implement a Debounced Search Input With Race-Condition-Safe Request Cancellation

Accepted Answer

**Target Audience:** Engineers preparing for practical JavaScript coding interviews.
**Difficulty:** Medium

> **How to read this doc:** the real bug this question is testing for — an EARLIER, slower request resolving AFTER a LATER, faster one, and incorrectly overwriting the correct, more recent result — was reproduced directly with a deliberately adversarial real timing setup, not just described in the abstract.

## 1. The problem, restated

Debouncing alone only reduces HOW OFTEN a real reque

Question 6

Infinite scroll list simulator

Accepted Answer

**Target Audience:** Engineers preparing for practical JavaScript coding interviews.
**Difficulty:** Hard

> **How to read this doc:** the real correctness requirement this question specifically tests — that MANY rapid, near-bottom scroll events must collapse into exactly ONE real `loadMore` call, not one per event — was verified directly: 3 rapid calls produced exactly 1 real trigger.

## 1. The problem, restated

On every real scroll event, check whether the scroll position is close enough to

JAVASCRIPT CODINGDECODED.

Medium

Wire Up Debounced Resize and Throttled Scroll Handlers on a Real Component

Implement throttle(func, wait, {leading, trailing})

Implement debounce() with leading/trailing and cancel/flush

Debounce async promise resolver

Implement a Debounced Search Input With Race-Condition-Safe Request Cancellation

Hard

Infinite scroll list simulator