#DECODER POLYBIUS SQUARE INSTALL#
#DECODER POLYBIUS SQUARE SERIES#

Typically, it is possible to arrange the letters however you like and read off the coordinates in whatever direction you like. Each letter is represented through a coordinate. The Polybius Square is a cipher that is achieved by arranging a typical alphabet into a grid. 'z' becomes 'c').Ĭaesar ( 'thinkful', 3 ) //> 'wklqnixo' caesar ( 'thinkful', - 3 ) //> 'qefkhcri' caesar ( 'wklqnixo', 3, false ) //> 'thinkful' caesar ( 'This is a secret message!', 8 ) //> 'bpqa qa i amkzmb umaaiom!' caesar ( 'BPQA qa I amkzmb umaaiom!', 8, false ) //> 'this is a secret message!' caesar ( 'thinkful' ) //> false caesar ( 'thinkful', 99 ) //> false caesar ( 'thinkful', - 26 ) //> false Polybius Square a shift of 3 on the letter 'z'), it should wrap around to the front of the alphabet (e.g.

If a letter is shifted so that it goes 'off' the alphabet (e.g.

Encoding is case-insensitive (e.g., both 'a' or 'A' would be encoded to the same result).

Spaces in the message should be maintained before and after encoding or decoding, as should other non-alphabetic symbols.

If the shift value is not present, equal to 0, less than -25, or greater than 25, the function should return false.

When building the function, keep the following constraints and rules in mind:

encode is a boolean that refers to whether you should encode or decode the message.

'A' becomes 'D') whereas a negative number means shifting to the left (i.e. A positive number means shifting to the right (i.e.

shift is an integer refers to how much each letter is 'shifted' by.

input is a string that refers to the inputted text to be encoded or decoded.

The caesar() function in the src/caesar.js file has three parameters: When decoding the message, you need to know the number the original message was shifted by so that you can shift in the opposite direction. It relies on taking the alphabet and 'shifting' letters to the right or left, based on the typical alphabetic order.įor example, if you were to 'shift' the alphabet to the right by 3, the letter 'A' would become 'D'.

The Caesar Shift is a type of substitution cipher originally used by Julius Caesar to protect messages of military significance.

Write tests for the substitution() function.

Write tests for the polybius() function.

Each function and cipher is described below.īelow is a checklist of what you need to accomplish.

#DECODER POLYBIUS SQUARE SERIES#

For each cipher, you should make a series of tests using Mocha & Chai to confirm that your cipher works.Īll of the functions can be found inside of the src/ directory, and the corresponding test files can be found in tests/. You are tasked with building functions for an application that will either encode or decode a string using a variety of ciphers. To stop the server and regain control of your terminal, you can press Ctrl + C.

To run the tests, you can run the following command:

#DECODER POLYBIUS SQUARE INSTALL#

Run npm install to install the dependencies needed for this project.Use different expect() methods to test your code.įollow the instructions below to get this project up and running on your own machine:.Write a series of unit tests using Mocha & Chai.This project will assess the following key learning objectives: You will not need to make any edits to HTML or CSS for this project. Before taking on this module, you should be comfortable with the learning objectives listed below. This project is designed to test your ability to build complex algorithms as well as write unit tests with Mocha & Chai to test your algorithms. What better way to practice your new coding skills than to build an application that will help you encode and decode all kinds of fun messages? You're planning a surprise birthday party for one of your friends who loves escape rooms and puzzles.

Decoder polybius square