Create factors.md

snippets/factors.md

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+### factors
+
+Returns the array of factors of the given `int`. If the second argument is set to `true` returns only the prime factors of `int`.If the third argument is set to `true` will return an array of arrays each containing two elements, the `factor` and the number of times the `factor` divides `int`.
+If `int` is `1` or `0` returns an empty array.
+If `int` is less than `0` returns all the factors of `-int` together with their `additive inverses`.
+
+**Note**:- _Negative numbers are not considered prime._
+``` js
+const factors = (int,prime = false,powers = false) => {
+  const howManyTimes = (num,divisor) => {
+    if([1,0].includes(divisor)) return Infinity
+    let i = 0
+    while(Number.isInteger(num/divisor)){
+      i++
+      num = num / divisor
+    }
+    return i
+  }
+  const isPrime = num => {
+  const boundary = Math.floor(Math.sqrt(num));
+  for (var i = 2; i <= boundary; i++) if (num % i == 0) return false;
+  return num >= 2 
+  }
+  let array = []
+  const posFactor = num => {
+  let arr = []
+  for (let i = 2; i <= num; i++) if (num % i === 0) arr.push(i)
+  return arr
+  }
+  if (int >= 0) array = posFactor(int)
+  else {posFactor(-int).forEach(el => array.push(el,-el))}
+  array =  prime ? array.filter(el => isPrime(el)) : array;
+  return powers ? array.map(x => [x,howManyTimes(int,x)]) : array
+};