22 lines
495 B
Markdown
22 lines
495 B
Markdown
---
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title: isPrime
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tags: math,beginner,intermediate
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---
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Checks if the provided integer is a prime number.
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- Check numbers from `2` to the square root of the given number.
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- Return `false` if any of them divides the given number, else return `true`, unless the number is less than `2`.
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```js
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const isPrime = num => {
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const boundary = Math.floor(Math.sqrt(num));
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for (var i = 2; i <= boundary; i++) if (num % i === 0) return false;
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return num >= 2;
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};
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```
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```js
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isPrime(11); // true
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```
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