Weekly Coding Challenge: Valid Parentheses – written in JavaScript

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2 min read ~ Hello readers! It’s really important for me to continue my practice and learning. Lately, I have been completing a coding challenge a day with codewars. This helps me keep my skills sharp and see how other devs all over the planet would solve these problems. Being able to see other solutions expands my mind for solving future problems in a clever and efficient way. Today, the problem set focuses on JavaScript.

Valid Parentheses

Write a function called that takes a string of parentheses, and determines if the order of the parentheses is valid. The function should return true if the string is valid, and false if it’s invalid.

"()"              =>  true
")(()))"          =>  false
"("               =>  false
"(())((()())())"  =>  true

JavaScript Solution

function validParentheses(parens){
    let parenArr = [];
    let parenObj = {'(': ')'}
    for (let i = 0; i < parens.length; i++) {
        if (parens[i] === '(') {
        else {
            let last = parenArr.pop(); 
            if (parens[i] !== parenObj[last]) {
              return false
    if (parenArr.length !== 0) {
      return false
    return true;

Disclaimer: *Now, as much as I am tempted to use ES8 & ES9 functions to reduce the number of lines in JavaScript, I am always a fan of readable code that others can understand. Therefore, with the JavaScript examples, I will try to write it without fancy functions as much as possible so it can actually be read and absorbed by my readers. All of my solutions are commented to explain my thinking. Of course, they could always be better. Please feel free to share how you would solve it!*

All solutions are also now on my GitHub profile if you want to check out all of the coding challenges I’ve completed so far!

All credit to problem sets goes to codewars

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