Exercises on the JavaScript Track | Exercism

Hello World

The classical introductory exercise. Just say "Hello, World!"

control flow conditionals

optional values

text formatting

Two Fer

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

optional values

text formatting

Resistor Color

Convert a resistor band's color to its numeric representation

Resistor Color Duo

Convert color codes, as used on resistors, to a numeric value.

Gigasecond

Given a moment, determine the moment that would be after a gigasecond has passed.

RNA Transcription

Given a DNA strand, return its RNA Complement Transcription.

Space Age

Given an age in seconds, calculate how old someone is in terms of a given planet's solar years.

floating point numbers

Pangram

Determine if a sentence is a pangram.

control flow conditionals

control flow loops

Matrix

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

control flow conditionals

control flow loops

data structures

text formatting

Bob

Bob is a lackadaisical teenager. In conversation, his responses are very limited.

control flow conditionals

pattern recognition

regular expressions

Pascal's Triangle

Compute Pascal's triangle up to a given number of rows.

control flow conditionals

control flow loops

text formatting

Linked List

Implement a doubly linked list

control flow conditionals

control flow loops

data structures

optional values

Grade School

Given students' names along with the grade that they are in, create a roster for the school

List Ops

Implement basic list operations

control flow loops

data structures

Robot Name

Manage robot factory settings.

control flow conditionals

exception handling

regular expressions

Simple Cipher

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

control flow conditionals

control flow loops

text formatting

Wordy

Parse and evaluate simple math word problems returning the answer as an integer.

control flow conditionals

control flow loops

exception handling

pattern recognition

regular expressions

Secret Handshake

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

bitwise operations

control flow conditionals

control flow loops

Leap

Given a year, report if it is a leap year.

Reverse String

Reverse a string

Collatz Conjecture

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

control flow conditionals

control flow loops

exception handling

Triangle

Determine if a triangle is equilateral, isosceles, or scalene.

control flow conditionals

control flow loops

exception handling

Clock

Implement a clock that handles times without dates.

Meetup

Calculate the date of meetups.

control flow conditionals

control flow loops

exception handling

ETL

We are going to do the `Transform` step of an Extract-Transform-Load.

control flow loops

Hamming

Calculate the Hamming difference between two DNA strands.

control flow conditionals

control flow loops

Raindrops

Convert a number to a string, the content of which depends on the number's factors.

control flow conditionals

Nucleotide Count

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

control flow conditionals

control flow loops

text formatting

Scrabble Score

Given a word, compute the scrabble score for that word.

control flow conditionals

control flow loops

Allergies

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

bitwise operations

control flow conditionals

control flow loops

Word Count

Given a phrase, count the occurrences of each word in that phrase.

control flow loops

regular expressions

Difference Of Squares

Find the difference between the square of the sum and the sum of the squares of the first N natural numbers.

control flow loops

Perfect Numbers

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

control flow conditionals

control flow loops

Complex Numbers

Implement complex numbers.

Luhn

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

control flow conditionals

control flow loops

Prime Factors

Compute the prime factors of a given natural number.

control flow conditionals

control flow loops

Grains

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

control flow loops

Pythagorean Triplet

There exists exactly one Pythagorean triplet for which a + b + c = 1000. Find the product a * b * c.

control flow conditionals

control flow loops

Palindrome Products

Detect palindrome products in a given range.

control flow conditionals

control flow loops

exception handling

Anagram

Given a word and a list of possible anagrams, select the correct sublist.

Acronym

Convert a long phrase to its acronym

control flow loops

regular expressions

High Scores

Manage a player's High Score list

Isogram

Determine if a word or phrase is an isogram.

Matching Brackets

Make sure the brackets and braces all match.

control flow conditionals

control flow loops

exception handling

Phone Number

Clean up user-entered phone numbers so that they can be sent SMS messages.

Series

Given a string of digits, output all the contiguous substrings of length `n` in that string.

control flow loops

exception handling

text formatting

Largest Series Product

Given a string of digits, calculate the largest product for a contiguous substring of digits of length n.

control flow conditionals

control flow loops

exception handling

regular expressions

Transpose

Take input text and output it transposed.

text formatting

Rectangles

Count the rectangles in an ASCII diagram.

control flow conditionals

control flow loops

Spiral Matrix

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

control flow conditionals

control flow loops

data structures

OCR Numbers

Given a 3 x 4 grid of pipes, underscores, and spaces, determine which number is represented, or whether it is garbled.

control flow conditionals

control flow loops

exception handling

text formatting

Saddle Points

Detect saddle points in a matrix.

control flow conditionals

control flow loops

exception handling

optional values

Forth

Implement an evaluator for a very simple subset of Forth

domain specific languages

Food Chain

Generate the lyrics of the song 'I Know an Old Lady Who Swallowed a Fly'

text formatting

House

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

control flow conditionals

control flow loops

ISBN Verifier

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

control flow conditionals

control flow loops

pattern recognition

regular expressions

Pig Latin

Implement a program that translates from English to Pig Latin

control flow conditionals

control flow loops

regular expressions

Proverb

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

control flow conditionals

control flow loops

optional values

text formatting

Twelve Days

Output the lyrics to 'The Twelve Days of Christmas'

control flow conditionals

control flow loops

pattern recognition

regular expressions

Beer Song

Produce the lyrics to that beloved classic, that field-trip favorite: 99 Bottles of Beer on the Wall.

control flow conditionals

control flow loops

Say

Given a number from 0 to 999,999,999,999, spell out that number in English.

control flow conditionals

control flow loops

exception handling

text formatting

Diamond

Given a letter, print a diamond starting with 'A' with the supplied letter at the widest point.

control flow conditionals

control flow loops

exception handling

text formatting

Rational Numbers

Implement rational numbers.

floating point numbers

Sublist

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

Binary Search Tree

Insert and search for numbers in a binary tree.

control flow conditionals

control flow loops

Custom Set

Create a custom set type.

control flow conditionals

control flow loops

data structures

Binary Search

Implement a binary search algorithm.

control flow conditionals

control flow loops

Circular Buffer

A data structure that uses a single, fixed-size buffer as if it were connected end-to-end.

control flow conditionals

control flow loops

data structures

exception handling

Simple Linked List

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

data structures

Word Search

Create a program to solve a word search puzzle.

control flow conditionals

control flow loops

optional values

text formatting

Variable Length Quantity

Implement variable length quantity encoding and decoding.

bitwise operations

Two Bucket

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

control flow conditionals

control flow loops

exception handling

Alphametics

Write a function to solve alphametics puzzles.

Connect

Compute the result for a game of Hex / Polygon

control flow conditionals

control flow loops

Bowling

Score a bowling game

control flow conditionals

control flow loops

exception handling

text formatting

Strain

Implement the `keep` and `discard` operation on collections. Given a collection and a predicate on the collection's elements, `keep` returns a new collection containing those elements where the predicate is true, while `discard` returns a new collection containing those elements where the predicate is false.

control flow conditionals

control flow loops

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.

control flow loops

Flatten Array

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

Nth Prime

Given a number n, determine what the nth prime is.

control flow conditionals

control flow loops

exception handling

Sieve

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

control flow conditionals

control flow loops

Rotational Cipher

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

control flow conditionals

text formatting

Diffie Hellman

Diffie-Hellman key exchange.

control flow conditionals

control flow loops

exception handling

Atbash Cipher

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

control flow conditionals

control flow loops

regular expressions

text formatting

Crypto Square

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

control flow conditionals

control flow loops

regular expressions

text formatting

Robot Simulator

Write a robot simulator.

control flow conditionals

control flow loops

exception handling

Kindergarten Garden

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

control flow conditionals

control flow loops

text formatting

Sum Of Multiples

Given a number, find the sum of all the multiples of particular numbers up to but not including that number.

control flow conditionals

control flow loops

Change

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

Protein Translation

Translate RNA sequences into proteins.

control flow conditionals

control flow loops

Armstrong Numbers

Determine if a number is an Armstrong number

Run Length Encoding

Implement run-length encoding and decoding.

control flow conditionals

exception handling

pattern recognition

regular expressions

text formatting

Darts

Write a function that returns the earned points in a single toss of a Darts game

Roman Numerals

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

control flow conditionals

control flow loops

pattern recognition

All Your Base

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

control flow conditionals

control flow loops

exception handling

Minesweeper

Add the numbers to a minesweeper board

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.

control flow conditionals

control flow loops

exception handling

optional values

text formatting

React

Implement a basic reactive system.

reactive programming

Zipper

Creating a zipper for a binary tree.

D&D Character

Randomly generate Dungeons & Dragons characters