Interview Q&A / Data Structures & Algorithms

1. When should you use a Map instead of a plain object in JavaScript?

   Use a Map when keys are not just strings, when you add and remove entries often, or when you need a reliable size and insertion order. Use a plain object for fixed, string-keyed records.

   BeginnerQuick answer1 min read
2. Why does [10, 9, 1].sort() return [1, 10, 9] in JavaScript?

   By default sort converts elements to strings and compares them in dictionary order, so "10" comes before "9". Pass a comparator such as (a, b) => a - b to sort numbers numerically.

   BeginnerQuick answerCoding1 min read