bd68b70f3d
* fix: remove isHidden flag from frontmatter * fix: add isUpcomingChange Co-authored-by: Ahmad Abdolsaheb <ahmad.abdolsaheb@gmail.com> * feat: hide blocks not challenges Co-authored-by: Ahmad Abdolsaheb <ahmad.abdolsaheb@gmail.com> Co-authored-by: Ahmad Abdolsaheb <ahmad.abdolsaheb@gmail.com>
86 lines
1.8 KiB
Markdown
86 lines
1.8 KiB
Markdown
---
|
|
id: 56533eb9ac21ba0edf2244ba
|
|
title: Understand String Immutability
|
|
challengeType: 1
|
|
videoUrl: 'https://scrimba.com/c/cWPVaUR'
|
|
forumTopicId: 18331
|
|
---
|
|
|
|
## Description
|
|
<section id='description'>
|
|
In JavaScript, <code>String</code> values are <dfn>immutable</dfn>, which means that they cannot be altered once created.
|
|
For example, the following code:
|
|
|
|
```js
|
|
var myStr = "Bob";
|
|
myStr[0] = "J";
|
|
```
|
|
|
|
cannot change the value of <code>myStr</code> to "Job", because the contents of <code>myStr</code> cannot be altered. Note that this does <em>not</em> mean that <code>myStr</code> cannot be changed, just that the individual characters of a <dfn>string literal</dfn> cannot be changed. The only way to change <code>myStr</code> would be to assign it with a new string, like this:
|
|
|
|
```js
|
|
var myStr = "Bob";
|
|
myStr = "Job";
|
|
```
|
|
|
|
</section>
|
|
|
|
## Instructions
|
|
<section id='instructions'>
|
|
Correct the assignment to <code>myStr</code> so it contains the string value of <code>Hello World</code> using the approach shown in the example above.
|
|
</section>
|
|
|
|
## Tests
|
|
<section id='tests'>
|
|
|
|
```yml
|
|
tests:
|
|
- text: <code>myStr</code> should have a value of <code>Hello World</code>.
|
|
testString: assert(myStr === "Hello World");
|
|
- text: You should not change the code above the specified comment.
|
|
testString: assert(/myStr = "Jello World"/.test(code));
|
|
|
|
```
|
|
|
|
</section>
|
|
|
|
## Challenge Seed
|
|
<section id='challengeSeed'>
|
|
|
|
<div id='js-seed'>
|
|
|
|
```js
|
|
// Setup
|
|
var myStr = "Jello World";
|
|
|
|
// Only change code below this line
|
|
myStr[0] = "H"; // Change this line
|
|
// Only change code above this line
|
|
|
|
```
|
|
|
|
</div>
|
|
|
|
|
|
### After Test
|
|
<div id='js-teardown'>
|
|
|
|
```js
|
|
(function(v){return "myStr = " + v;})(myStr);
|
|
```
|
|
|
|
</div>
|
|
|
|
</section>
|
|
|
|
## Solution
|
|
<section id='solution'>
|
|
|
|
|
|
```js
|
|
var myStr = "Jello World";
|
|
myStr = "Hello World";
|
|
```
|
|
|
|
</section>
|