Challenge Project mysterious species

script.js

// 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
};

let specimens = [];
let mutSpecimens = [];
let canSurvive = [];

// Creation of sequences
const pAequorFactory = (nr, array) => {
  const specimen = {specimen: nr,
  dna: array}
  specimens.push(specimen);
};
// Mutation of sequences
const mutate = (nr) => {
  const randBase = Math.floor(Math.random() * 15);
  const mutatedBase = randBase + 1;
  console.log('The mutated base sequence of DNA: ' + mutatedBase);
  let newBase = '';
  const specimensCopy = specimens[nr-1].dna;
  const string = specimensCopy.join(' ');
  let newS = string.split(' ');
  //console.log('this are', specimens);
  if (newS[randBase] === 'A') {
    const dnaBases = ['T', 'C', 'G'];
    newBase = dnaBases[Math.floor(Math.random() * 3)];
  } else if (newS[randBase] === 'T') {
    const dnaBases = ['A', 'C', 'G'];
    newBase = dnaBases[Math.floor(Math.random() * 3)];  
  } else if (newS[randBase] === 'C') {
    const dnaBases = ['A', 'T', 'G'];
    newBase = dnaBases[Math.floor(Math.random() * 3)];
  } else {
    const dnaBases = ['A', 'T', 'C'];
    newBase = dnaBases[Math.floor(Math.random() * 3)];
  }; 
  newS[randBase] = newBase;
  const temp = {specimen: nr,
  dna: newS}
  mutSpecimens.push(temp);
  
};
const compareDNA = (obj, mutObj, nr) => { 
  let counter = 0;
  for ( let i = 0 ; i < obj[nr-1].dna.length ; i++) {
    if (obj[nr-1].dna[i] === mutObj[nr-1].dna[i] ) {
      counter += 1;
    };
  };
  console.log(counter)
  const percentage = (100/obj[nr-1].dna.length)*counter;
  return 'The two DNA samples are: ' + percentage + '% in common!'
};
const willLikelySurvive = (obj) => { 
  let countSurvive = 0; 
  for ( let objNR = 0; objNR < obj.length; objNR++) { let counter = 0;
  for ( let i = 0 ; i < obj[objNR].dna.length ; i++) {
    if (obj[objNR].dna[i] === 'C' || obj[objNR].dna[i] === 'G') {
      counter += 1;
    };
  };
  
  const percentage = (100/obj[objNR].dna.length)*counter;
  if ( percentage >= 60) {
  countSurvive += 1;
  canSurvive.push(obj[objNR]);
  /*return true;  
  } else {
    return  false; */
    };
    if (countSurvive === 30) {
      break;
    }
};
};
/* create and mutate specimens */
const createNbrs = nr => {
for (let i = 1; i <= nr; i++) {
 pAequorFactory(i, mockUpStrand()); 
};
};
createNbrs(100);
willLikelySurvive(specimens);
console.log('pAequor that can survive:', canSurvive.length)
console.log(canSurvive);