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 strand of DNA containing 15 bases
const mockUpStrand = () => {
  const newStrand = []
  for (let i = 0; i < 15; i++) {
    newStrand.push(returnRandBase())
  }
  return newStrand
}

function pAequorFactory(num, arr) {
  return {
    specimenNum: num,
    dna: arr,
    mutate() {
      let ind = Math.floor(Math.random() * 15);
      let base = this.dna[ind];
      let newBase;
      do {
        newBase = returnRandBase();
        this.dna.splice(ind, 1, newBase);
      }
      while (base === newBase);
      return this.dna;
    },
    compareDNA(obj) {
      let count = 0;
      for (i = 0; i < this.dna.length; i++) {
        if (this.dna[i] === obj.dna[i]) {
          count++;
        };
      };
      const common = ((count / this.dna.length) * 100).toFixed(1);
      console.log('Specimen 1 and Specimen 2 have ' + common + '% DNA in common.')
    },
    willLikelySurvive() {
      let cg = 0;
      for (i = 0; i < this.dna.length; i++) {
        if (this.dna[i] === 'C' || this.dna[i] === 'G') {
          cg++;
        };
      };
     const survive = ((cg / this.dna.length) * 100);
     if (survive >= 60) {
       return true;
     } else {
       return false;
     } 
    }
  }
}

const survivors = [];

function create30() {
  let x = 1;
  while (survivors.length < 30) {
    const pAequor = pAequorFactory(x, mockUpStrand());
    if (pAequor.willLikelySurvive() === true) {
      survivors.push(pAequor);
      x++;
    };
  };
  return survivors;
}

create30();
console.log(survivors);