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.

Exercises

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Examples

Atbash Cipher

Create an implementation of the atbash cipher, an ancient encryption system created in the Middle East.

Nucleotide Count

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

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.

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

Luhn

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

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.

Minesweeper

Add the numbers to a minesweeper board

Secret Handshake

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

Sublist

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

Flatten Array

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

List Ops

Implement basic list operations

Change

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

Palindrome Products

Detect palindrome products in a given range.

Saddle Points

Detect saddle points in a matrix.

Kindergarten Garden

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

Two Fer

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

Matrix

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

Simple Cipher

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

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!

Protein Translation

Translate RNA sequences into proteins.

React

Implement a basic reactive system.

Forth

Implement an evaluator for a very simple subset of Forth

House

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

Simple Linked List

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

Connect

Compute the result for a game of Hex / Polygon

Tournament

Tally the results of a small football competition.

Twelve Days

Output the lyrics to 'The Twelve Days of Christmas'

Alphametics

Write a function to solve alphametics puzzles.

Complex Numbers

Implement complex numbers.

Dominoes

Make a chain of dominoes.

Poker

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

Spiral Matrix

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

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.

Zipper

Creating a zipper for a binary tree.

Isbn Verifier

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

Rail Fence Cipher

Implement encoding and decoding for the rail fence cipher.

Rectangles

Count the rectangles in an ASCII diagram.

Variable Length Quantity

Implement variable length quantity encoding and decoding.

Diffie Hellman

Diffie-Hellman key exchange.

Pov

Reparent a graph on a selected node

Proverb

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

Two Bucket

Given two buckets of different size, demonstrate how to measure an exact number of liters.

Word Search

Create a program to solve a word search puzzle.

Markdown

Refactor a Markdown parser

Zebra Puzzle

Solve the zebra puzzle.

Error Handling

Implement various kinds of error handling and resource management

Grep

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

Scale Generator

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

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.

Dot Dsl

Write a Domain Specific Language similar to the Graphviz dot language

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).

Reverse String

Reverse a string

Paasio

Report network IO statistics