Javascript 将Firebase元素映射为数组

我正在开发一个池投注应用程序。一切看起来都很好，我正在完成它的最后一个模块

在firebase中，我有一个赌注池，有很多用户。任何用户都有许多比赛，他们在比赛中下注。像这样：

 fetchPoolData = async () => {
    const { firebaseApp } = this.props;

    await firebaseApp
      .database()
      .ref(`/pools/${this.props.location.state.pool.key}/users`)
      .once("value")
      .then(snapshot => {
        this.setState({
          poolData: this.snapshotToArray(snapshot),
          isLoadingPool: false
        });
      });
  };

this.props.poolData.map(user => {
  allUserMatches.push(calculatePoints(user.matches, outcomeMatches));
});

Object.keys(user.matches)
(66) ["1", "2", "3", "4", "5", "6", "7", "8", "9", "10", "11", "12", "13", "14", "15", "16", "17", "18", "19", "20", "21", "22", "23", "24", "25", "26", "27", "28", "29", "30", "31", "32", "33", "34", "35", "36", "37", "38", "39", "40", "41", "42", "43", "44", "45", "46", "47", "48", "49", "50", "51", "52", "53", "54", "55", "56", "57", "58", "59", "60", "61", "62", "63", "64", "result", "topscorer"

当我在firebase上执行以下请求时：

 fetchPoolData = async () => {
    const { firebaseApp } = this.props;

    await firebaseApp
      .database()
      .ref(`/pools/${this.props.location.state.pool.key}/users`)
      .once("value")
      .then(snapshot => {
        this.setState({
          poolData: this.snapshotToArray(snapshot),
          isLoadingPool: false
        });
      });
  };

this.props.poolData.map(user => {
  allUserMatches.push(calculatePoints(user.matches, outcomeMatches));
});

Object.keys(user.matches)
(66) ["1", "2", "3", "4", "5", "6", "7", "8", "9", "10", "11", "12", "13", "14", "15", "16", "17", "18", "19", "20", "21", "22", "23", "24", "25", "26", "27", "28", "29", "30", "31", "32", "33", "34", "35", "36", "37", "38", "39", "40", "41", "42", "43", "44", "45", "46", "47", "48", "49", "50", "51", "52", "53", "54", "55", "56", "57", "58", "59", "60", "61", "62", "63", "64", "result", "topscorer"

一切看起来都很好。现在我有一个用户数组，我想进行一些计算，以获得每个用户在每次比赛中的得分。因此，我会像这样映射用户：

 fetchPoolData = async () => {
    const { firebaseApp } = this.props;

    await firebaseApp
      .database()
      .ref(`/pools/${this.props.location.state.pool.key}/users`)
      .once("value")
      .then(snapshot => {
        this.setState({
          poolData: this.snapshotToArray(snapshot),
          isLoadingPool: false
        });
      });
  };

this.props.poolData.map(user => {
  allUserMatches.push(calculatePoints(user.matches, outcomeMatches));
});

Object.keys(user.matches)
(66) ["1", "2", "3", "4", "5", "6", "7", "8", "9", "10", "11", "12", "13", "14", "15", "16", "17", "18", "19", "20", "21", "22", "23", "24", "25", "26", "27", "28", "29", "30", "31", "32", "33", "34", "35", "36", "37", "38", "39", "40", "41", "42", "43", "44", "45", "46", "47", "48", "49", "50", "51", "52", "53", "54", "55", "56", "57", "58", "59", "60", "61", "62", "63", "64", "result", "topscorer"

这里的问题是user.matches没有作为数组进行检索。相反，它就像一个大的json对象，我可以映射它并用我的数学来计算点

如何映射此元素？如果我做Object.keys，我只得到这样一个对象：

 fetchPoolData = async () => {
    const { firebaseApp } = this.props;

    await firebaseApp
      .database()
      .ref(`/pools/${this.props.location.state.pool.key}/users`)
      .once("value")
      .then(snapshot => {
        this.setState({
          poolData: this.snapshotToArray(snapshot),
          isLoadingPool: false
        });
      });
  };

this.props.poolData.map(user => {
  allUserMatches.push(calculatePoints(user.matches, outcomeMatches));
});

Object.keys(user.matches)
(66) ["1", "2", "3", "4", "5", "6", "7", "8", "9", "10", "11", "12", "13", "14", "15", "16", "17", "18", "19", "20", "21", "22", "23", "24", "25", "26", "27", "28", "29", "30", "31", "32", "33", "34", "35", "36", "37", "38", "39", "40", "41", "42", "43", "44", "45", "46", "47", "48", "49", "50", "51", "52", "53", "54", "55", "56", "57", "58", "59", "60", "61", "62", "63", "64", "result", "topscorer"

如果我做一个Object.entries，它仍然不是很有用（因为我需要在数组的对象上做一个查找，以获得由对象的atribute过滤的元素）

---

我在这里迷路了。怎么办

如果您想使用这种映射，可以使用

Object.keys(user.matches).map(key => user.matches[key])

上面将返回每个对象的关键点，稍后可以通过它们的关键点在对象的地图中使用这些关键点。 另外，它不会以数组的形式返回，因为您有两个与数组索引不同的野生属性（result和topcorer），所以它需要将它们作为对象而不是数组返回

一种从该键值对中检索所有值而不使用result和topcorer的方法

Object.keys(user.matches).filter(key => Number.isInteger(parseInt(key))).map(key => user.matches[key]). 

---

这将使用数字索引（类型字符串）将对象转换为所需的数组：

Object.keys(user.matches).reduce((arr, key) => {
  arr[parseInt(key)] = user.matches[key]
  return arr
}, [])

---

我想这更多的是关于将具有数字索引的对象转换为数组。您希望数据是什么样子的？如下：数组（66）0:{away_结果：“1”，away_团队：2，日期：“2018-06-14T18:00:00+03:00”，完成：false，组：“a”，…}1:{away_结果：“1”，away_团队：4，日期：“2018-06-15T17:00+05:00”，完成：false，组：“a”，…}2:{away_结果：“2”，away_团队：6，日期：“2018-06-15T21:00+03:00”是的，但是你想把它转换成什么样子呢？我想忘记firebase对我的物体所做的这些奇特的键。我想要一个好的旧数组，从0开始到66结束，这个数组的每个值都类似于“客场结果：”1，客场团队：2，日期：“2018-06-14T18:00:00+03:00”，完成：false“我没有得到它Siroo”。我在这里做的是，我的user.matches变成了这样一个数组：0:away\u结果：“1”away\u团队：2日期：“2018-06-14T18:00:00+03:00”finished:false组：“a”home\u结果：“1”home\u团队：1键：“1”name:1体育场：1类型：“group”原型：对象1：away\u结果：“1”away\u团队：4日期：“2018-06-15T17:00:00+05:00”这两个通配符属性没有问题，因为在这个值中，我有一个可以正确筛选的属性。但在该user.matches中也有两个看起来不像数组索引的属性（“result”，“topcorer”）因此Firebase将其作为对象字段返回，数组索引作为属性名，并返回结果和topscorer。如果您想删除这两个字段，还可以执行类似Object.keys（user.matches）.filter（key=>Number.isInteger（parseInt（key）））.map（key=>user.matches[key]）的操作。在上面这一行中，你将有数组元素的正常映射迭代，排除结果和TopCoreral。因此，我的建议是避免出现这样的情况：你想要一个数组，但无意中你添加了两个打破该结构的proeprities，这样Firebase会自动将其转换为对象键值对，而不是带有索引的数组。这样处理数据就容易多了，忘掉它吧。你告诉我的那个选择很有效。谢谢你，伙计！