Mysterious Organism

// Returns a random DNA base
const returnRandBase = () => {
  const dnaBases = ['A', 'T', 'C', 'G']
  return dnaBases[Math.floor(Math.random() * 4)] 
}

// Returns a random single stand of DNA containing 15 bases
const mockUpStrand = () => {
  const newStrand = []
  for (let i = 0; i < 15; i++) {
    newStrand.push(returnRandBase())
  }
  return newStrand
}

// 3
function pAequorFactory(num, arr){
    let obj = {
        specimenNum: num,
        dna: arr
    }

    // 4
    obj.mutate = function (){ 
        let arr = this.dna;
        let len = arr.length;
        let randomBase = arr[Math.floor(Math.random() * len)];
        let changeToBase = arr[Math.floor(Math.random() * len)]; 
        while(randomBase == changeToBase){
          chaangeToBase = arr[Math.floor(Math.random() * len)];
        }
        let changedArr = arr.map(ele => {
            if(ele == randomBase){
              return changeToBase;
            }
            return ele;
        })
        return changedArr;  
    },

    //5
    obj.compareDNA = function(obj){
        let thisDna = this.dna;
        let passedDna = obj.dna;
        let commons = 0;
          for(let i = 0 ; i < thisDna.length; i++){
            if(thisDna[i] == passedDna[i]){
              commons++;
            }
          }
        let per = Math.floor(commons / thisDna.length * 100);
        console.log(`specimen #1 and specimen #2 have ${per}% DNA in common`);
    },

    // 6
    obj.willLikelySurvive = function(){
        let gc = this.dna.filter(ele => {
            return ele == "C" || ele == "G";
        })
        return Math.floor(gc.length / this.dna.length * 100) >= 60;  
    }
  return obj;
}

console.log(pAequorFactory(returnRandBase(), mockUpStrand()));
/* Example Output
{ specimenNum: 'T',
  dna: [ 'G', 'T', 'G', 'A', 'G', 'T', 'T', 'G', 'G', 'C', 'A', 'T', 'C', 'A', 'C' ],
  mutate: [Function],
  compareDNA: [Function],
  willLikelySurvive: [Function] }
*/


// 7
let pAequors = [];
while(pAequors.length < 30){
  let specimen = pAequorFactory(returnRandBase(), mockUpStrand());
  if(specimen.willLikelySurvive()){
    pAequors.push(specimen);
  }
}
console.log(pAequors);


// Extra Practice
// CHECK WEATHER ALL THE INSTANCES IN pAequors CAN SURVIVE
let canSurvive = pAequors.filter(x => {
    return !x.willLikelySurvive();
})
if (canSurvive.length == 0){
  console.log("They all can survive");
};