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To check number is a prime number, looping through 2 to your given number-1 and check is any divisible number or not, if have means it’s not a prime number.

Note: 1 is considered neither prime nor composite.

Today, I’m going to show How do I check if the number is a prime number or not in Javascript, here I will create a custom function `isPrimeNumber()` where I will check if there have any divisible number based on this it will return a boolean value.

Let’s start the today’s tutorial How do you check if the number is prime in JavaScript?

In the following example

1. check given value is a number
2. check given value is greater than 1
3. check given value is prime or not
``````// function to check if a number is prime or not
// check if the passed value is a number
if (typeof number == 'number' && !isNaN(number)) {
if (number > 1) {
// looping through 2 to number-1
for (let i = 2; i < number; i++) {
if (number % i == 0) {
return false;
break;
}
}
return true;
}
}
return false;
} 