20 lines
470 B
Markdown
20 lines
470 B
Markdown
### isPrime
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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 * 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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isPrime(12) // false
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```
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