Demo of closure behaviour

closure-demo.js

"use strict";

class ExampleAsyncService {
  currentSearch = undefined;

  search(searchTerms) {
    this.currentSearch = searchTerms;

    console.log(`Searching for ${searchTerms}`);

    setTimeout(() => {
      if (this.currentSearch !== searchTerms) {
        console.log(`Search for ${searchTerms} superceded, aborting`);
      } else {
        console.log(`Search for ${searchTerms} complete`);
      }
    }, 500);
  }
}

const service = new ExampleAsyncService();

service.search("search1");
service.search("search2");
setTimeout(() => service.search("search3"), 600);