ColourGenerator class

class ColourGenerator {
  constructor () {
    this.map = new Map()
  }

  newColour (name) {
    const colour = '#'+((1<<24)*Math.random()|0).toString(16).padStart(6,'0')
    this.map.set(name, colour)
  }

  getColour (name) {
    if (!this.map.has(name)) this.newColour(name)
    return this.map.get(name)
  }
}

module.exports = new ColourGenerator()