While Loop Vs For Loop Javascript. For and while loops, fundamental control flow structures for iter
For and while loops, fundamental control flow structures for iteration, were introduced in early programming languages, with structured for loops appearing in ALGOL 60 (1960) and while loops also emerging around that time. Aug 30, 2024 · Loops allow us to repeatedly execute blocks of code in an efficient manner. Sep 18, 2025 · Master Python loops with detailed examples. 72M subscribers Subscribed 1. The Do While Loop The do while loop is a variant of the while loop. The For In Loop The forin loop iterates over the enumerable properties of an object. While-Loops are more flexible. Nov 13, 2011 · I've been always confused at the time to choose between the for and while loop. Aug 26, 2021 · In this tutorial, we learned about the while loop, the dowhile loop, and infinite loops in JavaScript. Oct 11, 2016 · What are the benefits of using a while loop over a for loop? When I'm iterating through arrays, I always use a for loop so I wondered if I'm missing something here. Instead of writing redundant code, you can run the code multiple times with a loop. Nov 3, 2025 · Loops offer a quick and easy way to do something repeatedly. I've noticed both in this group, in Stackoverflow and YouTube lots of false information about the Nodejs event loop. Your two loops, however, are semantically different. Types of loops in JavaScript The main types of loops in JavaScript are: For Loop: Ideal for known iteration counts. for-in loop: Specifically designed for iterating over an object's properties. This makes for more flexible stopping options for the programmer. Just use whichever loop seems more appropriate to the task at hand. If iterating determined number of times, go with the canonical for (var i = 0; i < MAX; i++) loop for readibility and maintainability's sake. I knew that Mozilla had made some trick to make for loops fast, but I didn’t imagine that Firefox would beat the While & Do-While: Learning the subtle difference—especially how a do-while loop guarantees the code runs at least once before checking the condition. In t 5 days ago · The do-while loop is similar to while loop except it executes the code block at least once before checking the condition. 🚀 New Video Alert – Web Development Series (HTML / CSS / JS) Just uploaded a brand new tutorial on Loops in JavaScript as part of my Web Development Series! If you’ve just started learning An infinite loop is a sequence of instructions in a computer program which loops endlessly, either due to the loop having no terminating condition, [3] having one that can never be met, or one that causes the loop to start over. Increment: Executed at the end of each iteration. The JavaScript while and do…while loops repeatedly execute a block of code as long as a specified condition is true. Jun 19, 2022 · In practice, the browser provides ways to stop such loops, and in server-side JavaScript, we can kill the process. The JavaScript for of statement loops through the values of an iterable object. Oct 30, 2025 · The for awaitof statement creates a loop iterating over async iterable objects as well as sync iterables. Nov 6, 2021 · This article provide you with detail understanding about the concept of loop inJavascript along with different types of Loops by Javascript. Jun 23, 2025 · Learn how to use for, for/in, for/of, while, do/while, and forEach loops in JavaScript with step-by-step examples and practical tips. The condition is evaluated after Jul 17, 2024 · Introduction Loops are fundamental constructs in JavaScript that enable repeated execution Tagged with javascript, webdev, web3, productivity. However, forEach() is actually an array method, so it can only be used exclusively with arrays. The while loop loops through a block of code as long as the specified condition evaluates to true. var slaying = true; Check out my courses and become more creative! https://developedbyed. The do while loop is a variant of the while loop. By using `break`, developers can exit a loop or switch block based on specific conditions, avoiding unnecessary iterations or case evaluations and optimizing program performance. length’. Jun 3, 2021 · 2. 2. The forin loop is primarily used for objects to access their property names (keys). While we partially agree, that got us thinking: “should programmers always prefer . The generic syntax of the while loop is: Jul 1, 2015 · I know the game works using a while loop, so I tried replicating it with a for loop but failed. prompt(`En For loops are well-suited for situations where the number of iterations is known and a more structured approach is desired. // while loop = repeat some code WHILE some condition is truelet loggedIn = false;let username;let password;while(!loggedIn){ username = window. Expression: Evaluated before each iteration, exits the loop when false. This loop will execute the code block once, before checking if the condition is true, then it will repeat the loop as long as the condition is true. Say we wanted to search through an array of contacts and telephone numbers and return just the number we wanted to find? Aug 26, 2021 · Popular topics Introduction Loops are used in programming to automate repetitive tasks. If you want the loop to break based on a condition other than the number of times it runs, you should use a while loop. A forin loop only iterates over enumerable, non-symbol properties. In this blog, we’ll delve into these loops, their syntax, use […] Im learning javascript and i noticed the two pretty much get the same job done the same way just different syntax. Both help in iteration, but they differ in syntax, control, and their specific use-cases. For while loops, make sure there is explicit logic that changes the state of the condition. Jul 29, 2019 · Loops play an essential role in software development, and they are used to iterate through the arrays or other elements which are iterable. Mar 8, 2024 · Compare the essential differences between for and while loops in JavaScript to improve your programming understanding. This chapter of the JavaScript Guide introduces the different iteration statements available to JavaScript. Jun 22, 2023 · Learn the power of iteration in JavaScript with for, while, and do-while loops. We would like to show you a description here but the site won’t allow us. In which situations should I use 'while loops' instead' for loops' in JavaScript? Does it make a difference? Feb 5, 2024 · What is the difference between while, do-while and for loops in JavaScript ? Loops are powerful control flow statements in JavaScript that allow you to execute a block of code repeatedly until a … Oct 6, 2020 · Thank you for this detailed breakdown of JavaScript's for-loop and while-loop! Your explanation makes it much easier to understand these fundamental concepts, especially for beginners. While all loops aim to achieve similar outcomes, each type Web Dev Roadmap for Beginners (Free!): https://bit. DoWhile Loop: Executes at least once, even if the condition is initially false. In JavaScript, there are currently two types of loop structures: The "for" loop and the "while" loop. NOTE: The forEach loop is another type of for loop in JavaScript. And many developers are familiar with loops, but not everyone understands how they work and why or when they should use a specific type of loop. You’ll learn about the three most commonly used loops Dec 14, 2020 · Measuring Performance of Different JavaScript Loop Types Optimize your JavaScript code by using the right loop types. Below is the working example with a while loop to give context. Apr 12, 2022 · JavaScript The Early Lessons: For Vs forEach Vs For Of. Aug 23, 2021 · Reduce repetitive programming tasks in JavaScript to a few lines of code with 'for' and 'while' loops. I've never had a situation where a for loop doesn't do the job, but I'm worried that I may be picking up bad habits here. 5K 99K views 4 years ago JavaScript Tutorial for Beginners Feb 15, 2020 · Loops are used in JavaScript to perform repeated tasks based on a condition. map, . Automation of repetitive tasks is an extremely important part of programming, and these loops can help make your programs more efficient and concise. forEach is a higher-order function that simplifies iteration with built-in array methods, while for loops offer more control, flexibility, and broader application. 2) JavaScript traditional for loop is the fastest I am really surprised with these results. The do while loop will execute the code block once, before checking if the condition is true, then it will repeat the loop as long as the condition is true. I was recently working on the Profile Lookup challenge, and had everything correct, but was using a While loop. Standard Array Functions and Operations in JavaScript Aug 22, 2024 · In JavaScript, both forEach and for loops are used to iterate over arrays or collections, but they differ in usage and behavior. You can view while as the most general kind of loop, with for being syntactic sugar for a while loop before which the initializer statement, and after each iteration an update statement is run. In general, you should use a for loop when you know how many times the loop should run. A language with for loops can only express programs that always terminate, it cannot express non-termination. In this video, we dive into JavaScript loops and explore how they are used to repeat tasks efficiently. However, they differ in their syntax and use cases. Say you want to start your loop from a specific index, you can do that with your traditional for loop but not using forof. The Difference Between For-, While, Do-While Loops (Overview) This page contains an overview of the three different loops in Java. Using a while loop in this problem might seem like a good idea, but it is not. Jul 21, 2025 · Learn JavaScript loops with step-by-step examples. Loop 3 (for in) — 1591 (1615. I Apr 30, 2024 · All for loops can be written as while loops, and vice-versa. The most basic types of loops used in JavaScript are the while and dowhile statements, which you can review in “ How To Construct While and Do…While Loops in JavaScript. Are there any performance differences between for and while loops? May 30, 2021 · 2. It finds widespread application in `for`, `while`, `dowhile` loops, and `switch` statements. Also instead of ‘x<4’, try ‘x<array. The keyword foris used, followed by three statements: 1. Recursive calls can lead to increased memory usage because each function call is added to the stack, while a loop only requires a single memory allocation. 2) Loop 2 (do – while) — 159 (167. Loops & Iteration, Which One Is Better? My articles are aimed at those people just starting out on their webdev journey, I am myself a Jr … JavaScript provides several options for looping: for loop: This is the most versatile loop that gives you full control over the iteration process. jusr making sure im not missing anything because then ill feel lost. 9) Chrome Loop 1 (for ;;) — 180 (191. I‘m now going to spend a little time and my friend while she’s in town. We'll look at how each one works, when to use them, and how to choose the right one for your specific needs with examples based on real-world scenarios. Oct 27, 2025 · Performance & The Better Way to Loop Objects 💡 While forin works, it can be less performant and sometimes loop through inherited properties. They should be exactly the same. Nov 5, 2019 · Taking a look at for loops and while loops as well as when and how to use each of them within your code. Example: The below JavaScript program do-while loop prints "Iteration:" followed by i, increments i by 1, and repeats the process while i is less than 3, ensuring the block runs at least once. 5 days ago · While Loop Traversal A while loop may also be applied to more general situations. for Loop Syntax for (initialization; condition; finalExpre A for loop is generally used if the number of loops is known, a while loop is generally for an unknown number of loops. Jan 22, 2025 · The main types of loops in JavaScript, including ‘for’ loops and ‘while’ loops, each have unique structures and use cases that can be leveraged for different programming needs. FORTRAN (1957) featured DO loops, which served as an early form of iteration but were closer to modern loops. Easy guide for beginners and pros. The while and for loops are two fundamental loop structures that provide different ways to iterate through data or execute tasks. It sometimes can be confusing which loop we should use in a particular case and which one will be the best in case of our performance. Jul 8, 2025 · The dowhile statement creates a loop that executes a specified statement as long as the test condition evaluates to true. It lets you loop over iterable data structures such as Arrays, Strings, Maps, NodeLists, and more: The key difference between the two is organization between them, if you were going to increase to 10 it’d be a lot cleaner and more readable to use a for statement, but on the other hand if you were to use an existing variable in your program in your loop parameters it’d be cleaner to just wright a while loop. A for loop is more structured than the while loop. For Loop Dec 16, 2025 · It's the same with loops — a break statement will immediately exit the loop and make the browser move on to any code that follows it. 🔔 Like • Comment • Share • Subscribe to support #EasyWebSeriesIn this video, we’ve covered JavaScript Loops in one complete session. Mar 11, 2018 · I am trying to understand use cases for each type of loop. Otherwise, your loop will never end and your browser may crash. forEach Array methods over simple loops in JavaScript?” Declarative programming style is very expressive, easier to write, and far more readable. The While loop got me an answer of “No such contact” everytime - the basic catch-all return value at the end of the function - no matter what variables where fed in. com Javascript For Loop and While Loop | Javascript Tutorial For Beginners In this video series we are going to learn modern May 19, 2025 · Learn how to master JavaScript loops—from for and while to forEach() and forof. In Javascript, we have a few different types of loops. This tutorial covers syntax and usage. Dec 1, 2019 · A while loop will execute as long as the given expression evaluates to true. They both come in several variations, and in this article we'll dig deeper into how they work and how you can use them. continue stops statement execution and goes to the next iteration of the loop. Jan 30, 2025 · In this article, I'll walk you through the main types of loops in JavaScript. This guide covers syntax, use cases, and tips to write efficient, scalable code. While Loop: Best for unknown iteration counts based on a condition. Jul 8, 2025 · The for statement creates a loop that consists of three optional expressions, enclosed in parentheses and separated by semicolons, followed by a statement (usually a block statement) to be executed in the loop. If you’ve just started learning JavaScript and feel confused about for loops, while loops, do-while loops, or how loops actually repeat code, this video will clear everything step by step. ” We would like to show you a description here but the site won’t allow us. It would be more meaningful to compare the above while-loop with the following for-loop: Jul 29, 2019 · In this article, I'll go through most popular Javascript loops, for loop, while loop, do while loop and others to compare their performance. One counts to zero, while the other counts to a property of an object, which is bound to be slower, though only slightly so. On the other hand, while loops are ideal when the number of iterations is unknown or when the loop's termination depends on a specific condition. It’s better 99% of the time, but not when performance matters. 71M subscribers Subscribed 1. While Loop Among the commonly used loops, the for loop and the while loop are the most widely used. Loops are essential tools in JavaScript (and programming in general) for executing a block of code repeatedly until a specified condition is met. A "while loop" loops as long as a condition is true. Find out now! Oct 24, 2016 · 5 For-loops are syntactic sugar for while loops. However, the choice between them depends on the specific requirements and the structure of the code. For-Loops allow running through the loop in the case you know the start- and endpoint in advance. In the second example, using let, the variable declared in the loop does not redeclare the variable outside the loop. Master art of repetitive execution to efficiently process data, automate tasks. In JavaScript, there are several types of loops that serve different purposes - Nov 28, 2018 · What is the difference between for loop and while loop? I am not asking about the syntax or how each loop works or do while is an exit controlled loop. Loops help us Jun 23, 2025 · Learn how JavaScript while and do…while loops work, when to use them, and how they differ — with clear examples and best practices. Aug 27, 2025 · When you’re working with loops in JavaScript, it’s common to get confused between forin and Tagged with javascript, webdev, programming, beginners. A "for loop" always loops for set number of times. Apr 20, 2022 · One of my bugbears with JS and Nodejs is the huge amount of confusion between the JS event loop as run by browsers, versus the Nodejs event loop which uses a different library and approach. Jul 29, 2025 · Like other looping statements, you can use control flow statements inside statement: break stops statement execution and goes to the first statement after the loop. The while Loop This is the simplest looping statement provided by JavaScript. 3. Learn the differences between for and while loops, understand their execution flow, and see real-world applications with complete output analysis. Jul 8, 2025 · The while statement creates a loop that executes a specified statement as long as the test condition evaluates to true. would you only use a while loop for a specific thing vs a for loop? or does it really not matter. If you think a performance gain is likely, you can easily benchmark it in the context of your project (and I think you'll find no observable difference, but I might be wrong). 6) Loop 3 (for in) — 585 (610. While-Loops do not necessarily need an adjusted endpoint. Nov 14, 2020 · Learn the differences between for and while loops in JavaScript, what happens when you accidentally create an infinite loop, and why you would want to use a The while Loop The while loop executes a block of code as long as a specified condition evaluates to true. Master for, while, and do-while loops to iterate through arrays and objects like a pro developer. while loop and do-while loop: These loops are useful when you don't know the exact number of iterations beforehand. reduce, and . As developers, we always push our limits to write better-performing applications … Jul 12, 2023 · Here are some scenarios where using loops might be a more suitable choice: Performance Concerns: Loops are generally more efficient than recursion regarding time and space complexity. The condition is evaluated before executing the statement. This statement can only be used in contexts where await can be used, which includes inside an async function body and in a module. When let is used to declare the i variable in a loop, the i variable will only be visible within the loop. 4 As for infinite loops for(;;) loop is better than while(1) since while evaluates every time the condition but again it depends on the compiler. Mar 9, 2024 · Inside the while loop, you should include the statement that will end the loop at some point of time. Jul 23, 2025 · Both for loops and while loops are control flow structures in programming that allow you to repeatedly execute a block of code. Debugging tools that allow stepping through code execution are invaluable for identifying the source of infinite loops. It is important for a beginner to know the key differences between both of them. . What I need to know is there must be a reason for creating for loop and while loop if the process done is same, then there is no need for the other, I am looking for that reason. Conditions typically return true or false. Any expression or variable can be a loop condition, not just comparisons: the condition is evaluated and converted to a boolean by while. ly/DaveGrayWebDevRoadmap In this video we'll look at several examples of Loops in Javascript and learn how to iterate thmore I have showed you the three types of loop which are While, Do while and For loop in Javascript. You can't access indices of your array elements natively. Feb 19, 2025 · Hey everyone! Today, let’s dive into an essential topic in JavaScript — loops! If you’ve ever needed to repeat a task multiple times in your code, loops are your best friend. Jun 10, 2014 · A language with while loops can compute any µ-recursive function, a language with for loops can only compute primitive-recursive functions. In the first example, using var, the variable declared in the loop redeclares the variable outside the loop. Aug 20, 2025 · Difference Between While Loop and For Loop in C++ Loops are one of the most important building blocks in programming. Sep 5, 2013 · The other day during a tech interview, one of the question asked was "how can you optimize Javascript code"? To my own surprise, he told me that while loops were usually faster than for loops. In this tutorial, you will learn about the JavaScript while and do…while loops with examples. A loop will continue running until the defined condition returns false. For Loop: An iteration structure that’s useful when the number of iterations is known. Aug 18, 2025 · Learn the key differences between Python for loop and while loop with practical examples, use cases, and code snippets. As soon as the condition fails, the loop is stopped. Initialization:Executed before the loop begins. The increment does not have to be ++, but you’ll see that the most Both for and while loops serve their purposes and can be used interchangeably in some cases. It is helpful when the constraints of the traversal are not known in advance, such as when traversing until a particular value is encountered. 4K 93K views 4 years ago JavaScript Tutorial for Beginners May 27, 2022 · Loops are a programming concept that we constantly encounter and implement as JavaScript developers. I'm curious primarily why the for loop isn't working and if there's some obvious reason this needs to be completed using a while loop. The while Loop The while loop executes a block of code as long as a specified condition evaluates to true. Loops are used to repeat Study with Quizlet and memorize flashcards containing terms like If/else statements, While loops, For loops and more. When I went to research, I found that the answer Aug 25, 2024 · JavaScript offers various looping mechanisms to iterate over code blocks, allowing developers to perform repetitive tasks efficiently.