Hi!
I'm Dom,
Data Scientist

I created a simple function in JavaScript to check if a word or sentence is a palindrome, meaning they are spelled the same way forward and backward, ignoring punctuation, case, and spacing. My approach is to convert the input string argument to lowercase and remove all non-word characters with regex. I then check whether that string is equivalent to a backwards version that was split into an array, reversed, and joined back into a string.

This JavaScript project is a function that converts Arabic numerals to Roman numerals. In my solution, I begin with an array of 13 descending values in Roman numerals, covering each unique numeral and their “minus one” condition) and a corresponding array of those values as integers. I use a while loop to find the index of the largest value in the integer array that can fit into the number to convert, then subtract that from said number and push the Roman numeral at the corresponding index to a result array. The result array is then joined into a string and returned.

I created this JavaScript function to decode a Caesar cipher, also known as a shift cipher, a type of substitution cipher in which each letter is replaced with the letter a set number of positions after it in the alphabet. My approach makes use of a “key” string with letters of the alphabet (A-Z) and a corresponding “value” string with the coded substitute values for each letter at the same index in the key. This general key-value-based approach can be used for any substitution cipher. To create the value string used here, for each index value in the key string I get the sum of that value and the shift value (i.e., 13), then use the remainder of the sum divided by the length of the key string as the index of the letter from the key to add to the value string. To decode the message, I iterate over the characters in the coded string argument. If a character is found in the value string, the index is returned and the letter in the key string at that index is added to the decoded message output. If a character is not found in the value string, then that character is added to the output.

I built this JavaScript function to check if a passed string is a valid US phone number. In this particular project only a handful of specific phone number formats were to be considered valid, so I constructed a fairly simple regular expression using capture groups, quantifiers, and character classes to test all potential cases.

For this project I designed a cash register drawer function in JavaScript that accepts a purchase price, payment, and cash-in-drawer argument, and returns an object with keys for the drawer status and an array of change to be returned (if applicable). To avoid floating point precision issues, I multiply all numerical values passed in the arguments by 100 and round the products to the nearest integer; this operation is performed on a deep copy (using JSON.parse/stringify) of the nested cash-in-drawer array to avoid mutation. Next, my function calls a reduce function to get the sum of cash-in-drawer, and if this is equal to the value of change to be returned, returns the “CLOSED” status and the original cash-in-drawer argument. For other conditions, my function uses while loop to iterate over the denominations available in the drawer from largest to smallest, and if the denomination is less than or equal to the remaining change to be returned, it subtracts the maximum available value of that denomination from the remaining change and pushes that value (divided by 100) and denomination to an array of change to return. Once the remaining change is zero or all denominations have been checked, my function returns the “OPEN” status and the array of change if the remaining change is zero, otherwise it returns the “INSUFFICIENT_FUNDS” status and an empty array.