A prime number (or a prime) is a natural number greater than 1 that cannot be formed by multiplying two smaller natural numbers. All other natural numbers greater than 1 are called composite numbers. A primality test is an algorithm for determining whether an input number is prime.
We are required to write a JavaScript function that takes in a number and checks whether it is a prime or not.
Example
Following is the code −
const findPrime = (num = 2) => { if (num % 1 !== 0) { return false; } if (num <= 1) { return false; } if (num <= 3) { return true; } if (num % 2 === 0) { return false; } const dividerLimit = Math.sqrt(num); for (let divider = 3; divider <= dividerLimit; divider += 2) { if (num % divider === 0) { return false; } } return true; }; console.log(findPrime(2)); console.log(findPrime(97)); console.log(findPrime(131)); console.log(findPrime(343));
Output
Following is the output on console −
true true true false