JavaScript Data Structures: Hash Table: Setup

Intro 🌐

Last time, we learned how to handle hash collisions.

Today, we'll use all of the stuff we learned so far to setup our Hash Table.

Requirements 💭

We need the following parts to setup our Hash Table:

• a Hash Table class
• a container for our data
• the size of the data
• a hash function that inputs a key and outputs an array index

Implementation ⛑

// a Hash Table class class Hashtable { constructor() { // a container for our data this.data = [] // the size of the data this.size = 0 } // a hash function that inputs a key and outputs an array index hash(key) { const chars = key.split('') const charCodes = chars.map(char => char.charCodeAt()) const charCodeSum = charCodes.reduce((acc, cur) => acc + cur) return charCodeSum } } 

If you are not familiar with the hash function, re-read this post.

Result

// create a new hash table const newHashtable = new Hashtable() // hash table should have no data and size 0 console.log(newHashtable) // Hashtable { data: [], size: 0 } ✅ 

Next Part ➡️

We'll learn how to add data to our Hash Table.

Need some mentoring? Click here!

Further Reading 📖

• Simple Wiki: Hash Table
• Wikipedia: Hash Table
• Wikibooks: Hash Table

Questions ❔

• How would you implement the Hash Table?
• How would you build the hash function? Why?