认为数据是

{
    "Groceries": [
        {
            "category": {
                "uri": "/categories/20fe3330-80e1-4908-9f57-5b7ef575b197",
                "parent": "Food & Drink",
                "name": "Groceries"
            },
            "amount": "85.14",
            "debit": true
        },
        {
            "category": {
                "uri": "/categories/20fe3330-80e1-4908-9f57-5b7ef575b197",
                "parent": "Food & Drink",
                "name": "Groceries"
            },
            "amount": "19.15",
            "debit": true
        },
        {
            "category": {
                "uri": "/categories/20fe3330-80e1-4908-9f57-5b7ef575b197",
                "parent": "Food & Drink",
                "name": "Groceries"
            },
            "amount": "4.2",
            "debit": true
        },
        {
            "category": {
                "uri": "/categories/20fe3330-80e1-4908-9f57-5b7ef575b197",
                "parent": "Food & Drink",
                "name": "Groceries"
            },
            "amount": "16.08",
            "debit": true
        },
        {
            "category": {
                "uri": "/categories/20fe3330-80e1-4908-9f57-5b7ef575b197",
                "parent": "Food & Drink",
                "name": "Groceries"
            },
            "amount": "28.48",
            "debit": true
        },
        {
            "category": {
                "uri": "/categories/20fe3330-80e1-4908-9f57-5b7ef575b197",
                "parent": "Food & Drink",
                "name": "Groceries"
            },
            "amount": "35.82",
            "debit": true
        },
        {
            "category": {
                "uri": "/categories/20fe3330-80e1-4908-9f57-5b7ef575b197",
                "parent": "Food & Drink",
                "name": "Groceries"
            },
            "amount": "12.15",
            "debit": true
        },
        {
            "category": {
                "uri": "/categories/20fe3330-80e1-4908-9f57-5b7ef575b197",
                "parent": "Food & Drink",
                "name": "Groceries"
            },
            "amount": "4.19",
            "debit": true
        },
        {
            "category": {
                "uri": "/categories/20fe3330-80e1-4908-9f57-5b7ef575b197",
                "parent": "Food & Drink",
                "name": "Groceries"
            },
            "amount": "34.11",
            "debit": true
        },
        {
            "category": {
                "uri": "/categories/20fe3330-80e1-4908-9f57-5b7ef575b197",
                "parent": "Food & Drink",
                "name": "Groceries"
            },
            "amount": "3.36",
            "debit": true
        },
        {
            "category": {
                "uri": "/categories/20fe3330-80e1-4908-9f57-5b7ef575b197",
                "parent": "Food & Drink",
                "name": "Groceries"
            },
            "amount": "11.32",
            "debit": true
        }
    ],
    "Restaurants": [
        {
            "category": {
                "uri": "/categories/15147702-8227-4ee8-8b05-d2e8d532bd0a",
                "parent": "Food & Drink",
                "name": "Restaurants"
            },
            "amount": "18.43",
            "debit": true
        }
    ]
} 

我所有想要的数据都类似于

{
    "Groceries": 1234.12, # (1234.12 is madeup value for now)added values for all Groceries transaction
    "Restaurents": 18.42
}

我正在使用Lodash来执行此操作,我的代码如下所示

var mapped = _.reduce(data, function(result, num, key){
  var sum = 0.0;
  sum = _.reduce(num, function(sum, n){
      console.log(key + ':' + parseFloat(n.amount));
      return sum + parseFloat(n.amount);
  });
  result[key] = sum;
  return result;
}, {})

我得到的结果是

"{
    "Groceries": "[object Object]19.154.216.0828.4835.8212.154.1934.113.3611.32",
    "Restaurants": {
        "category": {
            "uri": "/categories/15147702-8227-4ee8-8b05-d2e8d532bd0a",
            "parent": "Food & Drink",
            "name": "Restaurants"
        },
        "amount": "18.43",
        "debit": true
    }
}"

我在这里做错了什么？

解决方法:

从docs开始：

Reduces a collection to a value which is the accumulated result of running each element in the collection through the callback, where each successive callback execution consumes the return value of the previous execution. If accumulator is not passed, the first element of the collection will be used as the initial accumulator value

因此,您应该提供一个初始值或解析和,因为它是一个String对象,因此我建议您提供一个初始值,因为每次经过第一个解析都没有意义.

因此,您可以执行以下操作：

var s = _.reduce(num, function(sum, n){
  return sum + parseFloat(n.amount);
}, 0);