### Add new TypeScript exercises

One of the easiest ways to add new exercises to the TypeScript track is to translate them from other language tracks on Exercism. This page lists all of the problem specifications in the common pool of exercises which have not yet been implemented in TypeScript.

The icon links to the language-independent description of the problem.

The icon links to the canonical test data.

We also link to all the implementations of each exercise in other languages, which you can use for inspiration.

Once you've picked an exercise, follow the instructions in this guide and submit your pull request to the TypeScript track repository on GitHub.

### Roman Numerals

Write a function to convert from normal numbers to Roman Numerals.

### Grains

Calculate the number of grains of wheat on a chessboard given that the number on each square doubles.

### Nucleotide Count

Given a DNA string, compute how many times each nucleotide occurs in the string.

### Allergies

Given a person's allergy score, determine whether or not they're allergic to a given item, and their full list of allergies.

### Collatz Conjecture

Calculate the number of steps to reach 1 using the Collatz conjecture

### Isogram

Determine if a word or phrase is an isogram.

### Luhn

Given a number determine whether or not it is valid per the Luhn formula.

### Meetup

Calculate the date of meetups.

### Sieve

Use the Sieve of Eratosthenes to find all the primes from 2 up to a given number.

### All Your Base

Convert a number, represented as a sequence of digits in one base, to any other base.

### Perfect Numbers

Determine if a number is perfect, abundant, or deficient based on Nicomachus' (60 - 120 CE) classification scheme for natural numbers.

### Bracket Push

Make sure the brackets and braces all match.

### Crypto Square

Implement the classic method for composing secret messages called a square code.

### Accumulate

Implement the `accumulate` operation, which, given a collection and an operation to perform on each element of the collection, returns a new collection containing the result of applying that operation to each element of the input collection.

### Pig Latin

Implement a program that translates from English to Pig Latin

### Queen Attack

Given the position of two queens on a chess board, indicate whether or not they are positioned so that they can attack each other.

### Run Length Encoding

Implement run-length encoding and decoding.

### Secret Handshake

Given a decimal number, convert it to the appropriate sequence of events for a secret handshake.

### Flatten Array

Take a nested list and return a single list with all values except nil/null

### Minesweeper

Add the numbers to a minesweeper board

### Sublist

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

### Two Fer

Create a sentence of the form "One for X, one for me."

### Custom Set

Create a custom set type.

### List Ops

Implement basic list operations

### Saddle Points

Detect saddle points in a matrix.

### Change

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

### Palindrome Products

Detect palindrome products in a given range.

### Isbn Verifier

Check if a given string is a valid ISBN-10 number.

### Kindergarten Garden

Given a diagram, determine which plants each child in the kindergarten class is responsible for.

### Matrix

Given a string representing a matrix of numbers, return the rows and columns of that matrix.

### Protein Translation

Translate RNA sequences into proteins.

### React

Implement a basic reactive system.

### Simple Cipher

Implement a simple shift cipher like Caesar and a more secure substitution cipher

### Simple Linked List

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

### Transpose

Take input text and output it transposed.

### Bank Account

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

### Forth

Implement an evaluator for a very simple subset of Forth

### Alphametics

Write a function to solve alphametics puzzles.

### Connect

Compute the result for a game of Hex / Polygon

### House

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

### Twelve Days

Output the lyrics to 'The Twelve Days of Christmas'

### Complex Numbers

Implement complex numbers.

### Dominoes

Make a chain of dominoes.

### Spiral Matrix

Given the size, return a square matrix of numbers in spiral order.

### Tournament

Tally the results of a small football competition.

### 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.

### Parallel Letter Frequency

Count the frequency of letters in texts using parallel computation.

### Poker

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

### Rail Fence Cipher

Implement encoding and decoding for the rail fence cipher.

### Proverb

For want of a horseshoe nail, a kingdom was lost, or so the saying goes. Output the full text of this proverbial rhyme.

### Zipper

Creating a zipper for a binary tree.

### Armstrong Numbers

Determine if a number is an Armstrong number

### Diffie Hellman

Diffie-Hellman key exchange.

### Rectangles

Count the rectangles in an ASCII diagram.

### Variable Length Quantity

Implement variable length quantity encoding and decoding.

### Markdown

Refactor a Markdown parser

### Pov

Reparent a graph on a selected node

### Word Search

Create a program to solve a word search puzzle.

### Grep

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

### Error Handling

Implement various kinds of error handling and resource management

### Scale Generator

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

### Dot Dsl

Write a Domain Specific Language similar to the Graphviz dot language

### Go Counting

Count the scored points on a Go board.

### Sgf Parsing

Parsing a Smart Game Format string.

### Tree Building

Refactor a tree building algorithm.

### Hangman

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

### Ledger

Refactor a ledger printer.

### Lens Person

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

### Paasio

Report network IO statistics