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bodi
Asked:2024-11-12 04:35:10 +0000 UTC2024-11-12 04:35:10 +0000 UTC

我应该在代码中更改什么，以便可以迭代数组内的对象并输出所有内容

  • 772

const musicCollection = {
  albums: [{
      title: "Amends",
      artist: "Grey Daze",
      year: "2020"
    },
    {
      title: "Here on Earth",
      artist: "Tim McGraw",
      year: "2020"
    },
    {
      title: "Orquídeas",
      artist: "Karly Loaiza",
      year: "2024"
    }
  ]
}

musicCollection[Symbol.iterator] = function() {
  return {
    current: 0,
    to: this.albums.length,
    next() {
      return this.current < this.to ? {
        done: false,
        value: musicCollection[this.current++]
      } : {
        done: true
      };
    }
  }
}

for (let album of musicCollection) {
  console.log(`${album.title} - ${album.artist} (${album.year})`);
}

javascript

1 个回答

  1. Best Answer

    musicCollection排队

    musicCollection[this.current++]

    这是一个对象，它没有整数字段，但有一个字段albums包含它们。

    因此，要修复它，只需将上面的行替换为以下行

    musicCollection.albums[this.current++]


    const musicCollection = {
  albums: [{
      title: "Amends",
      artist: "Grey Daze",
      year: "2020"
    },
    {
      title: "Here on Earth",
      artist: "Tim McGraw",
      year: "2020"
    },
    {
      title: "Orquídeas",
      artist: "Karly Loaiza",
      year: "2024"
    }
  ]
}

musicCollection[Symbol.iterator] = function() {
  return {
    current: 0,
    to: this.albums.length,
    next() {
      return this.current < this.to ? {
        done: false,
        value: musicCollection.albums[this.current++]
      } : {
        done: true
      };
    }
  }
}

for (let album of musicCollection) {
  console.log(`${album.title} - ${album.artist} (${album.year})`);
}

    在某些情况下使用迭代器更容易使用生成器函数

    const musicCollection = {
  albums: [{
      title: "Amends",
      artist: "Grey Daze",
      year: "2020"
    },
    {
      title: "Here on Earth",
      artist: "Tim McGraw",
      year: "2020"
    },
    {
      title: "Orquídeas",
      artist: "Karly Loaiza",
      year: "2024"
    }
  ]
}

musicCollection[Symbol.iterator] = function* (){
  for(var i=0; i<this.albums.length; i++){
    yield this.albums[i];
  }
}

for (let album of musicCollection) {
  console.log(`${album.title} - ${album.artist} (${album.year})`);
}

    由于在这种情况下迭代器功能与已知的数组迭代器一致，因此您可以直接使用它：

    const musicCollection = {
  albums: [{
      title: "Amends",
      artist: "Grey Daze",
      year: "2020"
    },
    {
      title: "Here on Earth",
      artist: "Tim McGraw",
      year: "2020"
    },
    {
      title: "Orquídeas",
      artist: "Karly Loaiza",
      year: "2024"
    }
  ]
}

musicCollection[Symbol.iterator] = musicCollection.albums[Symbol.iterator].bind(musicCollection.albums);

for (let album of musicCollection) {
  console.log(`${album.title} - ${album.artist} (${album.year})`);
}

    • 3

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