83 lines
2.5 KiB
Markdown
83 lines
2.5 KiB
Markdown
---
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title: Comments
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---
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## Comments
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Programmers use comments to add hints, notes, suggestions, or warnings to their source code; they have no effect on the actual output of the code. Comments can be very helpful in explaining the intent of what your code is or should be doing.
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It is always best practice when starting out to comment more often than not, as it can help those reading your code to understand what exactly your code is intending to do.
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JavaScript has two ways of assigning comments in its code.
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The first way is the `//` comment; all text following `//` on the same line is considered as a comment. For example:
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```javascript
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function hello() {
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// This is a one line JavaScript comment
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console.log("Hello world!");
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}
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hello();
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```
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The second way is the `/* */` comment, which can be used for both single-line and multi-line comments. For example:
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```javascript
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function hello() {
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/* This is a one line JavaScript comment */
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console.log("Hello world!");
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}
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hello();
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```
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```javascript
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function hello() {
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/* This comment spans multiple lines. Notice
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that we don't need to end the comment until we're done. */
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console.log("Hello world!");
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}
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hello();
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```
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You can also prevent execution of Javascript code just commenting the code lines like this:
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```javascript
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function hello() {
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/*console.log("Hello world!");*/
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}
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hello();
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```
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#### More Information:
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<a href='https://www.digitalocean.com/community/tutorials/how-to-write-comments-in-javascript' target='_blank' rel='nofollow'>How To Write Comments in JavaScript</a>
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<h3>Many IDEs come with a keyboard shortcut to comment out lines. </h3>
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<ol>
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<li>Highlight text to be commented</li>
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<li>Mac: Push Command(Apple Key) & "/"</li>
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<li>Windows: Push Control & "/"</li>
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<li>You can also uncomment code by doing the same steps</li>
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</ol>
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A shortcut to comment out a section of javascript in many code editors is to highlight the lines of code you want to comment out, then press `Cmd/Ctrl + /`.
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Comments are also very helpful for code testing as you can prevent a certain code-line/block from running
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```javascript
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function hello() {
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// The statement below is not going to get executed
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// console.log('hi')
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}
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hello();
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```
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```
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function hello() {
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// The statements below are not going to get executed
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/*
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console.log('hi');
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console.log('code-test');
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*/
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}
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hello();
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```
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#### More Information:
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* <a href='https://www.digitalocean.com/community/tutorials/how-to-write-comments-in-javascript' target='_blank' rel='nofollow'>How To Write Comments in JavaScript</a>
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