sport-game.js

/**
 * As part of a technical screening interview I was requested to create a function
 * able to calculate the total score of a game after all of the given rounds were completed
 * following the criteria below:
 *
 * The function receives an array of strings restricted to the following operation:
 * Integer: Directly represents the number of points scored this round.
 * +: The points scored this round are the sum of the last two valid round's points.
 * D: The points scored this round are double the last valid round's points.
 * C: The last valid round's points were invalid and should not be counted towards the total score or any future operations.
 *
 * @parameter: {String[]} routine - Given round
 * @return: {Number} result of the game
 *
 * @example
 *
 * ```js
 * console.log(getTotalScoreOfTheGame(['5', '2', 'C', 'D', '+']) === 30) // => true
 * ```
 */

// I'm really gonna expect an array of strings
const UnexpectedInputError = new Error(`Unexpected input`)

// Your job is to calculate the total score of the game
// after all of the rounds are complete
function getTotalScoreOfTheGame (routine) {
  if (!Array.isArray(routine)) {
    throw UnexpectedInputError
  }

  const rounds = []

  routine.forEach(v => {
    if (typeof v !== 'string') {
      throw UnexpectedInputError
    }

    // Integer: Directly represents the number of points scored this round.
    if (/^[\d]+$/.test(v)) {
      return rounds.push(parseInt(v))
    }

    // "+": The points scored this round are the sum of the last two valid round's points.
    if (v === '+' && rounds.length >= 2) {
      return rounds.push(rounds.slice(-1)[0] + rounds.slice(-2)[0])
    }

    // "D": The points scored this round are double the last valid round's points.
    if (v === 'D' && rounds.length > 0) {
      return rounds.push(rounds.slice(-1)[0] * 2)
    }

    // "C": The last valid round's points were invalid and should not be counted towards the total score or any future operations.
    if (v === 'C' && rounds.length > 0) {
      return rounds.pop()
    }
  })

  return rounds.reduce((a, b) => {
    return a + b
  }, 0)
}

console.log('Sport game test', getTotalScoreOfTheGame(['5', '2', 'C', 'D', '+']) === 30 ? '' : 'NOT', 'passed')
console.log('Sport game test', getTotalScoreOfTheGame(['5', '10', '5', 'C', 'D', '+']) === 65 ? '' : 'NOT', 'passed')
console.log('Sport game test', getTotalScoreOfTheGame(['5', '10', '5', '23', 'C', 'C', 'D', '+']) === 65 ? '' : 'NOT', 'passed')

// Sport game test  passed
// Sport game test  passed
// Sport game test  passed