Codecademy export

main.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
}

const pAequorFactory = (number,dnaBases) => {
  return {
    specimenNum: number,
    dna: dnaBases,
    mutate () {
      const dnaBases = ['A', 'T', 'C', 'G'];
      let dnaMutated = Math.floor(Math.random()*15);
      let indexOfDNAMutated = dnaBases.indexOf(this.dna[dnaMutated]);
      let prevBases = dnaBases.slice(0,indexOfDNAMutated);
      let postBases = dnaBases.slice(indexOfDNAMutated+1,dnaBases.length)
      let candidateDNABases = prevBases.concat(postBases);
      this.dna[dnaMutated] = candidateDNABases[Math.floor(Math.random()*3)];
      return this.dna;
    },
    compareDNA (pAequor) {
      let sameDNA = 0;

      for (let i = 0; i < this.dna.length; i++) {
        if (this.dna[i] === pAequor.dna[i]) {
          sameDNA++;
        }
      }

      console.log(`specimen #${this.specimenNum} and specimen #${pAequor.specimenNum} have ${(sameDNA/this.dna.length).toFixed(2)*100}% DNA in common`)
    },
    willLikelySurvive () {
      let countOfCAndG = 0;
      for (let d = 0; d < this.dna.length; d++) {
        if (this.dna[d] === 'C' || this.dna[d] === 'G') {
          countOfCAndG++;
        }
      }

      return (countOfCAndG/this.dna.length) >= 0.6;
    }
    }
}



let specimenNumber = 1;
let survivorsCount = 0;
let survivors = [];

while (survivorsCount < 30) {
  let pAequorCaught = pAequorFactory(specimenNumber,mockUpStrand());
  if (pAequorCaught.willLikelySurvive()) {
    survivors.push(pAequorCaught);
    survivorsCount++;
  }
  specimenNumber++;
}

console.log(survivors)