javascript - 映射数组元素并返回对象

Question

我有一个像这样的对象数组:

var pools = [{
    dce: 3,
    lts: 2,
    name: "nift nation",
  },
  {
    dce: 1049.99,
    lts: 104.999,
    name: "NSG I.NS. Mark Select",
  },
  {
    dce: 162,
    lts: 36.157,
    name: "Shift-Team Mark Select",
  }
]

我得到:

[
  {
    "nift_nation": [
      {
        "nift_nationDollars": ""
      },
      {
        "nift_nationUnits": ""
      },
      {
        "nift_nationPercentage": ""
      }
    ]
  },
  {
    "NSG_I$NS$_Mark_Select": [
      {
        "NSG_I$NS$_Mark_SelectDollars": ""
      },
      {
        "NSG_I$NS$_Mark_SelectUnits": ""
      },
      {
        "NSG_I$NS$_Mark_SelectPercentage": ""
      }
    ]
  },
  {
    "Shift__Team_Mark_Select": [
      {
        "Shift__Team_Mark_SelectDollars": ""
      },
      {
        "Shift__Team_Mark_SelectUnits": ""
      },
      {
        "Shift__Team_Mark_SelectPercentage": ""
      }
    ]
  }
]

var pools = [{
    dce: 3,
    lts: 2,
    name: "nift nation",
  },
  {
    dce: 1049.99,
    lts: 104.999,
    name: "NSG I.NS. Mark Select",
  },
  {
    dce: 162,
    lts: 36.157,
    name: "Shift-Team Mark Select",
  }
]

var getFieldSuffix = function(rowFieldCount) {
  switch (rowFieldCount) {
    case 0:
      return 'Dollars';
    case 1:
      return 'Units';
    case 2:
      return 'Percentage';
    default:
      return
  }
};

var replacementMap = {
  single_space: '_',
  dot: '$',
  hyphen: '__',
};

var replacer = function(str) {
  return str.replace(/[ .-]/g, l => {
    if (l == ".") return replacementMap["dot"];
    if (l == " ") return replacementMap["single_space"];
    return replacementMap["hyphen"];
  });
};

var arrObj = pools.map(function(pool) {
  return Object.assign({
    [replacer(pool.name)]: ['Dollars', 'Units', 'Percentage'].map(function(suffix, index) {
      return {
        [replacer(pool.name) + getFieldSuffix(index % 3)]: ''
      }
    })
  })
})

console.log(arrObj)

我想要:

{
  {
    "nift_nation": {
      "nift_nationDollars": "",
      "nift_nationUnits": "",
      "nift_nationPercentage": "",
    }
  },
  {
    "NSG_I$NS$_Mark_Select": {
      "NSG_I$NS$_Mark_SelectDollars": "",
      "NSG_I$NS$_Mark_SelectUnits": "",
      "NSG_I$NS$_Mark_SelectPercentage": "",
    }
  },
  {
    "Shift__Team_Mark_Select": {
      "Shift__Team_Mark_SelectDollars": "",
      "Shift__Team_Mark_SelectUnits": "",
      "Shift__Team_Mark_SelectPercentage": "",
    }
  } 
}

Answer 1

您可以使用reduce()方法代替map()。

像这样:

return Object.assign({
    [replacer(pool.name)]: ['Dollars', 'Units', 'Percentage'].reduce(function(acc, suffix, index) { 
        acc[replacer(pool.name) + getFieldSuffix(index % 3)] = ''; 
        return acc;
     }, {})
  })

不同之处在于，当您使用map时，您返回一个数组。而使用reduce，你会返回累加器的结果，在这种情况下，它是一个对象，然后会被修补到你的父对象中。

然后可以将其应用于整个转换，如下所示:

var arrObj = pools.reduce(function(acc, pool) {
  acc[replacer(pool.name)] = ['Dollars', 'Units', 'Percentage'].reduce(function(acc, suffix, index) { 
        acc[replacer(pool.name) + getFieldSuffix(index % 3)] = ''; 
        return acc;
     }, {});
   return acc;
}, {})