为什么只是通过？我想知道更多我需要解释

Question

我写了另一个答案。但是我不明白这个。

.. 虽然，我运行 chrome 调试器，但我不能很好地理解。

result = true
// is passed

不是很懂。我提交了另一个答案，但我想知道为什么它只是通过。我需要解释更多，我想从这段代码中修复。

function isPrime(num) {
let result;
for(let i = 1 ; i <= num ; i++) {
  if(num[i] / num[i] === 1 && num[i] / num[i] === num[i]){
    result = true
  } else {
    result = false
  }
}
  return result
}
debugger;
let output = isPrime(2);
console.log(output); // --> true

output = isPrime(6);
console.log(output); // --> false

output = isPrime(17);
console.log(output); // --> true

Answer 1

根据维基百科，

A prime number (or a prime) is a natural number greater than 1 that is not a product of two smaller natural numbers. For example, 5 is prime because the only ways of writing it as a product, 1 × 5 or 5 × 1, involve 5 itself.

function isPrime (num) {
  // step 1: filter 1, negative numbers and decimal numbers
  if (num === 1 || num < 0 || num % 1 !== 0) {
    return false;
  }

  // step 2: dividing num by smaller numbers
  let divisor = num - 1;

  while (divisor > 1) {
    const remainder = num % divisor;

    // if num is divisible by dividing a smaller number, it's not a prime
    if (remainder === 0) {
      return false;
    }

    divisor -= 1;
  }

  // num is a prime
  return true;
}

let output = isPrime(2);
console.log(output); // --> true

output = isPrime(6);
console.log(output); // --> false

output = isPrime(17);
console.log(output); // --> true

output = isPrime(1);
console.log(output); // --> false

output = isPrime(-12);
console.log(output); // --> false

output = isPrime(78.25);
console.log(output); // --> false

output = isPrime(-12.5);
console.log(output); // --> false

为什么只是通过？我想知道更多我需要解释

Why is it just pass? i want to know more i need explained

javascript

closures

scope

if-statement