Car Factory

Car.js

class Car {
  constructor(length, doors) {
    try {
      if (doors < 1)
        throw 'We cannot enter a doorless car.'
      if (length < 7)
        throw 'We cannot build that small car.'
      if (length / doors < 1 || (length-3) < (doors*2))
        throw 'We cannot fit that many doors in that car.'
    } catch(e) {
      new Exception(e)
    }
    
    this.length = length
    this.doors = doors
  }
  
  makeRoof() {    
    return ` ${this.parts.roof.repeat(this.length - 3)}`
  }

  makeDoors() {
    const rearDoors = new Array(this.doors >= 2 ? Math.floor(this.doors/2) : 0).fill(this.parts.door)
    const frontDoors = new Array(this.doors >= 2 ? Math.ceil(this.doors/2) : 0).fill(this.parts.door)
    const emptySpaces = ' '.repeat((this.length - 3) - (this.doors * 2))

    if (this.doors === 1) {
      frontDoors.push(this.parts.door)
    }
    
    return `|${rearDoors.join('')}${emptySpaces}${frontDoors.join('')}\\`
  }

  makeChassis() {
    let axles = 2
    if (this.length >= 12) {
      this.length % 2
        ? axles = (this.length - 11)/2 + 2
        : axles = (this.length - 12)/2 + 3
    }

    const rearAxles = new Array(axles >= 2 ? Math.ceil(axles/2) : 0).fill(this.parts.axle)
    const frontAxles = new Array(axles >= 2 ? Math.floor(axles/2) : 0).fill(this.parts.axle)
    const emptySpaces = '-'.repeat((this.length - 2) - (Math.ceil(axles) * 2))

    return `-${rearAxles.join('')}${emptySpaces}${frontAxles.join('')}'`
  }
  
  get parts() {
    return {
      roof: '_',
      door: '[]',
      axle: 'o-',
    }
  }

  get body() {
    return {
      component: `${this.makeRoof()}\n${this.makeDoors()}\n`
    }
  }
  
  get chassis() {
    return {
      component: this.makeChassis()
    }
  }
}