hashtable.js

// assume we have an array called "list_of_items"
// that contains the names of over 1 million items
// first we'll create a new hash table that will allow
// us to later search for elements very quickly
let hashtable = {};
for (let item of list_of_items) {
  if (!hashtable[item]) {
    hashtable[item] = true;
  } 
}


// now searching is much faster
console.log(hashtable['The Great Gatsby']); // => will return true or undefined
console.log(hashtable['Kindle Fire']);
console.log(hashtable['Amazon Echo']);