builder pattern

class Frog {
  constructor(name, gender, eyes, legs, scent, tongue, heart, weight, height) {
    this.name = name;
    this.gender = gender;
    this.eyes = eyes;
    this.legs = legs;
    this.scent = scent;
    this.tongue = tongue;
    this.heart = heart;
    if (weight) {
      this.weight = weight;
    }
    if (height) {
      this.height = height;
    }
  }
}

class FrogBuilder {
  constructor(name, gender) {
    // Ensure that the first character is always capitalized
    this.name = name.charAt(0).toUpperCase() + name.slice(1);
    this.gender = gender;
  }

  formatEyes(eyes) {
    return Array.isArray(eyes) ? { left: eyes[0], right: eyes[1] } : eyes;
  }

  setEyes(eyes) {
    this.eyes = this.formatEyes(eyes);
    return this;
  }

  setLegs(legs) {
    if (!Array.isArray(legs)) {
      throw new Error('"legs" is not an array');
    }
    this.legs = legs;
    return this;
  }

  setScent(scent) {
    this.scent = scent;
    return this;
  }

  setTongue(tongue) {
    this.tongue = tongue;
    return this;
  }

  setHeart(heart) {
    this.heart = heart;
    return this;
  }

  setWeight(weight) {
    if (typeof weight !== 'undefined') {
      this.weight = weight;
    }
    return this;
  }

  setHeight(height) {
    if (typeof height !== 'undefined') {
      this.height = height;
    }
    return this;
  }

  build() {
    return new Frog(
      this.name,
      this.gender,
      this.eyes,
      this.legs,
      this.scent,
      this.tongue,
      this.heart,
      this.weight,
      this.height
    );
  }
}

const larry = new FrogBuilder('larry', 'male')
  .setEyes([{ volume: 1.1 }, { volume: 1.12 }])
  .setScent('sweaty socks')
  .setHeart({ rate: 22 })
  .setWeight(6)
  .setHeight(3.5)
  .setLegs([{ size: 'small' }, { size: 'small' }, { size: 'small' }, { size: 'small' }])
  .setTongue({ tongueWidth: 18, color: 'dark red', type: 'round' })
  .build();