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;
};

// dnaBases, array of 15 DNA bases
const pAequorFactory = (number, dnaBases) => {
  const pAequor = {
    specimenNum: number,
    dna: dnaBases,
    mutate() {
      const randomIndex = Math.floor(Math.random() * dnaBases.length - 1);
      const dnaToBeReplaced = this.dna[randomIndex];
      do {
        this.dna[randomIndex] = returnRandBase();
      } while (this.dna[randomIndex] !== dnaToBeReplaced)
    },
    compareDNA(otherDna) {
      let counter = 0;
      for (let i = 0; i < otherDna.dna.length; i++) {
        if (this.dna[i] === otherDna.dna[i]) {
          counter++;
        }
      }
      console.log(`specimen #${this.specimenNum} and specimen #${otherDna.specimenNum}
       have ${ (+counter / +this.dna.length) * 100}% DNA in common. `);
      return +counter / +this.dna.length * 100;
    },
    willLikelySurvive() {
      let counter = 0;
      counter = this.dna.reduce((acc, curr) => curr === 'C' || curr === 'G' ? ++acc : acc, 0);
      return counter / this.dna.length >= 0.6;
    },
    complementStrand() {
      let dnaMap = new Map([['A', 'T'], ['T', 'A'], ['C', 'G'], ['G', 'C']]);
      return this.dna.map(dna => dnaMap.get(dna));
    }
  };
  return pAequor;
};

const stuff = pAequorFactory(0, mockUpStrand());

const createStuff = function (index, num, arr) {
  if (index === num) {
    return arr;
  }
  const stuff = pAequorFactory(index, mockUpStrand());
  if (stuff.willLikelySurvive()) {
    arr.push(stuff);
    index++;
    return createStuff(index, num, arr);
  }
  return createStuff(index, num, arr);
};

const samples = createStuff(0, 30, []);
// input: array of dna objects
// output: the dna pair with the most similarity
// - take out the dna
// - compare the dna with the next one
// - check if result is higher than current result
// - if make max the two objects
function findMaxDNAPair(currIndex, arr, max, dnaPair) {
  //base case: if currIndex == array.length
  if (currIndex === arr.length) {
    return [dnaPair, max];
  } else {
    for (let i = currIndex + 1; i < arr.length; i++) {
      const currDna = arr[currIndex];
      const nexDna = arr[i];
      const similarity = currDna.compareDNA(nexDna);
      if (similarity > max) {
        max = similarity;
        dnaPair = [currDna, nexDna];
      }
    }
  }
  return findMaxDNAPair(currIndex + 1, arr, max, dnaPair);
}

console.log(findMaxDNAPair(0, samples, 0, []));