95 lines
3.6 KiB
Markdown
95 lines
3.6 KiB
Markdown
---
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title: Switch Statements
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---
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## Switch Statements
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<!-- The article goes here, in GitHub-flavored Markdown. Feel free to add YouTube videos, images, and CodePen/JSBin embeds -->
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A `switch` statement in programming is similar to an `if-else` statement, but has the benefit of sometimes being easier to read when there are a lot of conditions. Also it allows a `default` block to be added that will be executed if none of the other conditions are true.
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### Syntax:
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```javascript
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switch(expression) {
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case 1:
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console.log('1');
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break;
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case 2:
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console.log('2');
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break;
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default:
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console.log('No true condition, default');
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}
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```
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The above snippet shows the syntax for a basic `switch` statement. In this example, there are 3 different scenarios for:
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- `expression = 1`: First condition is true, and `1` gets printed to the console.
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- `expression = 2`: Second condition is true, and `2` gets printed to the console.
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- `expression = 'anything else'`: Case 1 and Case 2 are both false, so the default condition is executed.
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The `default` condition is a condition that will be executed if none of the other cases are true.
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**Note: One really important point is that in the snippet above, `case 1:` and `case 2:` might seem to represent some kind of order, but `1` and `2` are just possible answers which the `(expression)` may be evaluated to. The cases can be anything which the `(expression)` may evaluate to and can be tested against. A case may be a number, string, boolean, etc.**
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For example:
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```javascript
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var someValue;
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var expression = someValue;
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switch(expression){
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case someValue:
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console.log('10'); // 10 would be printed to the console
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break;
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case 23:
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console.log('12');
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break;
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default:
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console.log('No matches');
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}
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```
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Note: `expression` in the snippet above can be a string or number.
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### Break
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The `break` keyword is required in each case to make sure that only the code in that case gets executed. Without the break, multiple cases could be executed. When JavaScript reaches a `break` keyword, it breaks out of the switch block. If the `break` was left out of the above example, this is what would happen:
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```javascript
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var expression = 1;
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switch(expression) {
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case 1:
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console.log('1'); // 1 would be printed to console
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case 2: // As there is no break after case 1, this case is also executed.
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console.log('2'); // 2 would be printed to the console.
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break; // break -> Switch statement is exited
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default:
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console.log('No true condition, default');
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}
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```
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### Execute multiple cases:
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`switch` statements also allow for the same code block to be executed by multiple cases. This can be done by adding 1 or more `case :` keywords before a code block.
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Eg:
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```javascript
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switch (day) {
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case 4:
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case 5:
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console.log('it is nearly the weekend');
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break;
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case 0:
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case 6:
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console.log('it is the weekend');
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break;
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default:
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console.log('Looking forward to the Weekend');
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}
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```
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In the above snippet:
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- If `day` is `4` or `5` (Thursday or Friday), `it is nearly the weekend` will be printed to the console as the first case gets executed.
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- If `day` is `0` or `6`, (Saturday or Sunday),`it is the weekend` will be printed to the console as the second case gets executed.
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- If `day` is any other value, `Looking forward to the Weekend` will be printed to the console, as the default case gets executed.
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### More Information:
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<!-- Please add any articles you think might be helpful to read before writing the article -->
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<a href='https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Statements/switch' target='_blank' rel='nofollow'>MDN Documentation for switch</a>
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