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freeCodeCamp/curriculum/challenges/english/02-javascript-algorithms-and-data-structures/basic-javascript/iterate-with-javascript-while-loops.md

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---
id: cf1111c1c11feddfaeb1bdef
title: Iterate with JavaScript While Loops
challengeType: 1
videoUrl: 'https://scrimba.com/c/c8QbnCM'
forumTopicId: 18220
dashedName: iterate-with-javascript-while-loops
---
# --description--
You can run the same code multiple times by using a loop.
chore(learn): audit javascript algorithms and data structures (#41092) * chore(learn): audit basic algorithm scripting * chore(learn): audit basic data structures * chore(learn): audit basic javascript * chore(learn): audit debugging * chore(learn): audit es6 * chore(learn): audit functional programming * chore(learn): audit intermidate algorithms * chore(learn): audit js projects * chore(learn): audit object oriented programming * chore(learn): audit regex * fix(learn): remove stray . * fix(learn): string to code * fix(learn): missed some * fix(learn): clarify strings Based on Randy's feedback, clarifies string instances where quotes were removed in favour of back ticks. * fix: apply suggestions - thanks Randy! :) Co-authored-by: Randell Dawson <5313213+RandellDawson@users.noreply.github.com> * fix: non-suggestion comments * chore(learn): remove comments from codes Removes the comments from the description and instruction code blocks to ensure that all relevant information is translatable. * fix: Apply suggestions from code review Co-authored-by: Shaun Hamilton <51722130+ShaunSHamilton@users.noreply.github.com> * fix: revert crowdin fix * Update curriculum/challenges/english/02-javascript-algorithms-and-data-structures/basic-algorithm-scripting/mutations.md Co-authored-by: Randell Dawson <5313213+RandellDawson@users.noreply.github.com> * fix: Apply suggestions from code review Co-authored-by: Shaun Hamilton <51722130+ShaunSHamilton@users.noreply.github.com> * Update curriculum/challenges/english/02-javascript-algorithms-and-data-structures/es6/use-destructuring-assignment-to-assign-variables-from-arrays.md Co-authored-by: Shaun Hamilton <51722130+ShaunSHamilton@users.noreply.github.com> * fix: Apply suggestions from code review Co-authored-by: Oliver Eyton-Williams <ojeytonwilliams@gmail.com> Co-authored-by: Shaun Hamilton <51722130+ShaunSHamilton@users.noreply.github.com> * chore: change voice * fix: Christopher Nolan * fix: expressions would evaluate * fix: will -> would * Update curriculum/challenges/english/02-javascript-algorithms-and-data-structures/object-oriented-programming/add-methods-after-inheritance.md Co-authored-by: Randell Dawson <5313213+RandellDawson@users.noreply.github.com> * fix: to work to push * Update curriculum/challenges/english/02-javascript-algorithms-and-data-structures/basic-javascript/iterate-with-javascript-for-loops.md Co-authored-by: Shaun Hamilton <51722130+ShaunSHamilton@users.noreply.github.com> * Update curriculum/challenges/english/02-javascript-algorithms-and-data-structures/object-oriented-programming/add-methods-after-inheritance.md Co-authored-by: Randell Dawson <5313213+RandellDawson@users.noreply.github.com> Co-authored-by: Randell Dawson <5313213+RandellDawson@users.noreply.github.com> Co-authored-by: Shaun Hamilton <51722130+ShaunSHamilton@users.noreply.github.com> Co-authored-by: Oliver Eyton-Williams <ojeytonwilliams@gmail.com>
2021-03-02 16:12:12 -08:00
The first type of loop we will learn is called a `while` loop because it runs while a specified condition is true and stops once that condition is no longer true.
```js
var ourArray = [];
var i = 0;
while(i < 5) {
ourArray.push(i);
i++;
}
```
In the code example above, the `while` loop will execute 5 times and append the numbers 0 through 4 to `ourArray`.
Let's try getting a while loop to work by pushing values to an array.
# --instructions--
Add the numbers 5 through 0 (inclusive) in descending order to `myArray` using a `while` loop.
# --hints--
You should be using a `while` loop for this.
```js
assert(code.match(/while/g));
```
`myArray` should equal `[5,4,3,2,1,0]`.
```js
assert.deepEqual(myArray, [5, 4, 3, 2, 1, 0]);
```
# --seed--
## --after-user-code--
```js
if(typeof myArray !== "undefined"){(function(){return myArray;})();}
```
## --seed-contents--
```js
// Setup
var myArray = [];
// Only change code below this line
```
# --solutions--
```js
var myArray = [];
var i = 5;
while(i >= 0) {
myArray.push(i);
i--;
}
```