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7 posts tagged with "interview"

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· 3 min read
Xiaohai Huang
  1. How do you decide when to run useLayoutEffect?

    Ans: useLayoutEffect is a version of useEffect that fires before the browser repaints the screen.

    • Measuring layout before the browser repaints the screen.
    • Blocks the browser from repainting.
  2. The execution order of useEffect and useLayoutEffect.

    Execution TimingRuns after the render is committed to the screen. This means it runs after the browser has painted changes to the screen.Runs synchronously after all DOM mutations. This means it runs before the browser has a chance to paint, making it suitable for reading layout from the DOM and synchronously re-rendering.
    Use CasesMost side effects (data fetching, subscriptions)DOM manipulation, measuring elements, critical layout updates
    PerformanceGenerally better performance due to async natureCan impact performance if used excessively, as it blocks the browser from repainting

· One min read
Xiaohai Huang
  1. Browser cache. - cookie.
  2. Breadth-First Traversal and Depth First Traversal.
  3. script tag. async and defer.
  4. React Hook
var obj = {
a: 1,
foo: function (b) {
b = b || this.a;
return function (c) {

var a = 2;
var obj2 = { a: 3 };, 1);;

· 2 min read
Xiaohai Huang

When we are discussing about my projects. The interviewer asked the following questions:

  1. How do you achieve infinite play effect in a carousel?
  2. Use JS to achieve #id's scroll to element effect.
  3. CSS animation.

After done talking my projects, I was asked a few questions about Promise, linked list, and heap sort, insertion sort.