Add new exercises to JavaScript

One of the easiest ways to add new exercises to the JavaScript track is to translate them from other language tracks on Exercism. This page lists all of the exercises that exist on Exercism, but have not yet been implemented in JavaScript.

The icon links to the generic, language-independent problem description

The icon links to the canonical test data

The language icons link to each existing implementation of the problem.

Once you've picked an exercise, follow the instructions in the Contributing Guide and submit your pull request to the JavaScript track repository on GitHub.





Add the numbers to a minesweeper board

List Ops

Implement basic list operations


Write a function to determine if a list is a sublist of another list.

Bank Account

Simulate a bank account supporting opening/closing, withdraws, and deposits of money. Watch out for concurrent transactions!


Correctly determine change to be given using the least number of coins


Output the nursery rhyme 'This is the House that Jack Built'.


Compute the result for a game of Hex / Polygon

Parallel Letter Frequency

Count the frequency of letters in texts using parallel computation.


Implement a basic reactive system.

Simple Linked List

Write a simple linked list implementation that uses Elements and a List


Tally the results of a small football competition.


Take input text and output it transposed.

Twelve Days

Output the lyrics to 'The Twelve Days of Christmas'


Make a chain of dominoes.


Implement an evaluator for a very simple subset of Forth


Pick the best hand(s) from a list of poker hands.


Write a function to solve alphametics puzzles.

Protein Translation

Translate RNA sequences into proteins.

Rail Fence Cipher

Implement encoding and decoding for the rail fence cipher.

Variable Length Quantity

Implement variable length quantity encoding and decoding.


Creating a zipper for a binary tree.


Reparent a graph on a selected node


Count the rectangles in an ASCII diagram.

Rotational Cipher

Create an implementation of the rotational cipher, also sometimes called the Caesar cipher.

Book Store

To try and encourage more sales of different books from a popular 5 book series, a bookshop has decided to offer discounts of multiple-book purchases.


Search a file for lines matching a regular expression pattern. Return the line number and contents of each matching line.

Word Search

Create a program to solve a word search puzzle.

Zebra Puzzle

Solve the zebra puzzle.

Diffie Hellman

Diffie-Hellman key exchange.


Refactor a Markdown parser

Scale Generator

Generate musical scales, given a starting note and a set of intervals.

Sgf Parsing

Parsing a Smart Game Format string.

Dot Dsl

Write a Domain Specific Language similar to the Graphviz dot language

Go Counting

Count the scored points on a Go board.


Implement the logic of the hangman game using functional reactive programming.


Refactor a ledger printer.

Lens Person

Use lenses to update nested records (specific to languages with immutable data).

Tree Building

Refactor a tree building algorithm.

Error Handling

Implement various kinds of error handling and resource management


Report network IO statistics