ab617a762a
Improved IDE shortcut section by including linux and reworking list and made shortcuts clearer by using <kbd> for buttons
101 lines
3.0 KiB
Markdown
101 lines
3.0 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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The third way is the `/** */` comment, a format popularly known as JSDoc, can be used to clearly describe functions, classes, methods, and variables in your codebase in a detailed way. For example:
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```javascript
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/**
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* Adds two numbers together
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*
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* @param {number} num1 - first parameter
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* @param {number} num2 - second parameter
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* @returns {number}
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*/
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function addTwoNumbers(num1, num2) {
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return num1 + num2;
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}
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console.log(addTwoNumbers(10,20)) // will print 30 in the console.
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In some cases you may want to prevent code from running for debugging purposes. For example:
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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> Use hotkeys to comment out highlighted block
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<ul>
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<li>Mac: Push <kbd>Command</kbd> + <kbd>/</kbd></li>
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<li>Windows: Push <kbd>Control</kbd> + <kbd>/</kbd></li>
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<li>Most Linux Distros: Push <kbd>Shift</kbd> + <kbd>Alt</kbd> + <kbd>A</kbd></li>
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</ul>
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</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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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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