62 lines
1.3 KiB
Markdown
62 lines
1.3 KiB
Markdown
---
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title: While Loop
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---
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The `while` loop starts by evaluating the condition. If the condition is true, the statement(s) is/are executed. If the condition is false, the statement(s) is/are not executed and the `while` loop ends. `while` loops deserve some attention, since you will create an infinite loop if the false condition is never met. An infinite loop can crash your application or browser, so make sure all the `while` loops in your code are finite.
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Here is the **syntax** for the `while` loop:
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## Syntax:
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```javascript
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while (condition) {
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statement(s);
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}
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```
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_statement(s):_ A statement that is executed as long as the condition evaluates to true.
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_condition:_ Here, condition is a Boolean expression which is evaluated before each pass through the loop. If this condition evaluates to true, statement(s) is/are executed. When condition evaluates to false, execution continues with the statement after the while loop.
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## Example:
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```javascript
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let i = 1;
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while (i < 10) {
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console.log(i);
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i++; // same as i = i + 1
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}
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Output:
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1
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2
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3
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4
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5
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6
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7
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8
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9
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```
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## Example of an infite loop:
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```javascript
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let x = 0;
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while (x < 10) {
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console.log(x);
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x--; // same as i = i - 1
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}
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Output:
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0
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-1
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-2
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-3
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-4
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-5
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-6
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-7
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-8
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-9
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...etc.
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```
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### Other Resources
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* [MDN - while](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Statements/while)
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