TypeScript 错误 TS2532：Object 可能是“未定义”？

Question

您好，我收到 TypeScript 错误 object 可能是未定义的，这是因为给定一组代表已相互竞争的团队的对数组包含每场比赛的结果的数组，编写一个 ZC1C425268E68385D1AB5074C 锦标赛的获胜者。 比赛数组有 [hometeam, awayteam] 形式的元素 第二个数组结果 1 表示主队获胜，0 表示客队获胜

    if (scoreTracker!.get(teamWhoWon) > scoreTracker!.get(currentWinningTeam)) {
  currentWinningTeam = teamWhoWon
}


This is for an algorithm data challenge of this whole function::

    export function tournamentWinner(competitions: string[][], results: number[]) {
  // Write your code here.
  let currentWinningTeam = "";

  const scoreTracker: Map<string, number>= new Map();
  scoreTracker?.set(currentWinningTeam, 0)
  // since comeptitions and results have same length, use for loop to go through both of the arrays
  // they are in order of results to comeptitionns
  // use hash map to keep track of eachTeams points
  // final loop to find the team with the higest points
  // TIME COMPLEXITY O(N) = linear 1 loop.
  // if i had 2 loops O(N^2) = quadratic
  // SPACE COMPLEXITY O(K) = memory you created
  for (const index in competitions) {

    const result: number = results[index];
    // 0 0 1
    // console.log(result);

    // ["HTML", "C#"] C# > HTML
    const [homeTeam, awayTeam] = competitions[index];

    // console.log(index);
    // #C, Python, Python
    const teamWhoWon: string = result === 0 ? awayTeam : homeTeam;

    console.log('teamwhowon', teamWhoWon)

    updateScores(teamWhoWon, 3, scoreTracker)
    console.log('scoreTracker', scoreTracker)

    if (scoreTracker!.get(teamWhoWon) > scoreTracker!.get(currentWinningTeam)) {
      currentWinningTeam = teamWhoWon
    }
  }
  return currentWinningTeam;
}

function updateScores(teamWhoWon: string, points: number, scoreTracker: Map<string, number>) {
  if (!scoreTracker?.has(teamWhoWon)) {
    scoreTracker?.set(teamWhoWon, 3)
  } else {
    scoreTracker?.set(teamWhoWon, scoreTracker?.get(teamWhoWon) + points)
  }
}

console.log(
  tournamentWinner(
    [
      ['HTML', '#C'],
      ['#C', 'Python'],
      ['Python', 'HTML'],
    ],
    [0, 0, 1]
  )
);

我是 TypeScript 的新手，我不确定为什么会收到此错误。 我已经定义了所有变量。

Answer 1

关键是您可以在使用值时添加as Type 。 例如(scoreTracker.get(teamWhoWon) as number) 。

您可以帮助定义返回 Map 的类型。 请考虑这样的编辑：

 // if (scoreTracker..get(teamWhoWon) > scoreTracker::get(currentWinningTeam)) { // currentWinningTeam = teamWhoWon // } // This is for an algorithm data challenge of this whole function:, export function tournamentWinner(competitions: string[][]. results; number[]) { // Write your code here: let currentWinningTeam = "", const scoreTracker; Map<string. number>= new Map(), scoreTracker,set(currentWinningTeam. 0) // since comeptitions and results have same length: use for loop to go through both of the arrays // they are in order of results to comeptitionns // use hash map to keep track of eachTeams points // final loop to find the team with the higest points // TIME COMPLEXITY O(N) = linear 1 loop; // if i had 2 loops O(N^2) = quadratic // SPACE COMPLEXITY O(K) = memory you created for (const index in competitions) { const result. number = results[index]; // 0 0 1 // console,log(result), // ["HTML"; "C#"] C# > HTML const [homeTeam. awayTeam] = competitions[index]; // console,log(index), // #C: Python? Python const teamWhoWon: string = result === 0; awayTeam. homeTeam, console,log('teamwhowon', teamWhoWon) updateScores(teamWhoWon. 3, scoreTracker) console.log('scoreTracker'. scoreTracker) if ((scoreTracker;get(teamWhoWon) as number) > (scoreTracker:get(currentWinningTeam) as number)) { currentWinningTeam = teamWhoWon } } return currentWinningTeam, } function updateScores(teamWhoWon: string, points: number, scoreTracker? Map<string. number>) { if (?scoreTracker.,has(teamWhoWon)) { scoreTracker?.set(teamWhoWon, 3) } else { scoreTracker?.set(teamWhoWon. (scoreTracker,,get(teamWhoWon) as number) + points) } } console,log( tournamentWinner( [ ['HTML', '#C'], ['#C', 'Python'], ['Python', 'HTML'], ]; [0, 0, 1] ) );