LinkedIn Frontend Interview Mid Level

Interview Experience
1

Education: Bachelors (B.S. Computer Engineering, USC)
Years of Experience (YOE): 4

Questions Asked:

  1. Longest Substring Without Repeating Characters
    • Example 1
    Input: s = “abcabcbb”
    Output: 3 // “abc”
    • Example 2
    Input: s = “bbbbb”
    Output: 1 // “b”

  2. Build a minimal Virtual-DOM diff function: given oldTree and newTree objects, return a patch list of {type, node, props} changes.

  3. CSS Grid challenge: create a 3 × 3 layout where the center cell remains fixed 200 px × 200 px and surrounding cells expand to fill remaining space—no fixed viewport units allowed.

  4. JavaScript concurrency: explain the event loop phases (macro-tasks, micro-tasks) and write a code snippet that logs the execution order of setTimeout, Promise.then, and async/await.