Discussion on: React.js - Interview Question - duplicate hashtag remover.

[samselfridge]

You're calling set state for every new duplicate item, maybe react will batch this and save you, but don't count on it. You're better off initalizing a new array, pushing duplicates on to it then calling setState 1 time at the end.

  const findDuplicateTags = () => {
    let tagsMap = new Map();
    const duplicates = [];
    hashtags.split(" ").forEach((tag) => {
      tag = tag.trim();
      if (tag) {
        if (tagsMap.has(tag)) {
          duplicates.push(tag);
        } else {
          tagsMap.set(tag, 0);
        }
      }
    });
    setDuplicates(duplicates);
  };

Other things to note:

• This doesn't check for # as a tag so it would delete duplicate words
• Doesn't handle additional whitespace, look at String.trim()

Nice use of Map. Not bad for a interview but that repeated setState will absolutely destroy your apps performance and due to the async nature of setState could even get you into unpredictable behavior.

[Rajesh Royal]

hehe true I should have used this method. But there were many factors - and the biggest one was time bounding and it makes person nervous. I will be keeping it in mind.
Thank you.