Json：json数组的总和值

Question

以下是我的输入：

输入1 =

  [{

    "201609": 5,
    "201610": 7,
    "201611": 9,
    "201612": 10,
    "FY17": 24,
    "metric": "metric1",
    "careerLevelGroups": [{
        "201609": 3,
        "201610": 6,
        "201611": 9,
        "201612": 8
        "FY17": 18,
        "careerLevel": "Senior Managing Director",
        "careerLevels": [{
                "201609": 1,
                "201610": 2,
                "201611": 3,
                "201612": 5
                "FY17": 6,
                "careerLevel": "CL1"
            },
            {
                "201609": 2,
                "201610": 4,
                "201611": 6,
                "201612": 9
                "FY17": 12,
                "careerLevel": "CL2"
            }
        ]
    }]
}]

输入2 =

   [{

        "201609": 4,
        "201610": 8,
        "201611": 12,

        "FY17": 24,
        "metric": "metric1",
        "careerLevelGroups": [{
            "201609": 9,
            "201610": 2,
            "201611": 7,
            "FY17": 18,
            "careerLevel": "Senior Managing Director",
            "careerLevels": [{
                    "201609": 3,
                    "201610": 6,
                    "201611": 9,
                    "FY17": 18,
                    "careerLevel": "CL1"
                },
                {
                    "201609": 7,
                    "201610": 8,
                    "201611": 9,
                    "FY17": 24,
                    "careerLevel": "CL2"
                }
            ]
        }]
    }]

输出 = 输入 1 + 输入 2。

我的输出应该是所有数值的总和。如果没有 找到匹配的键如“201612”，它仍应保留该键 输出。

 [{

    "201609": 9,
    "201610": 15,
    "201611": 21,
    "201612": 10,
    "FY17": 48,
    "metric": "metric1",
    "careerLevelGroups": [{
        "201609": 12,
        "201610": 8,
        "201611": 16,
        "201612": 8,
        "FY17": 24,
        "careerLevel": "Senior Managing Director",
        "careerLevels": [{
                "201609": 4,
                "201610": 8,
                "201611": 12,
                "201612": 5,
                "FY17": 24,
                "careerLevel": "CL1"
            },
            {
                "201609": 9,
                "201610": 12,
                "201611": 15,
                "201612": 9,
                "FY17": 36,
                "careerLevel": "CL2"
            }
        ]
    }]
}]

下面是我正在尝试做的事情：

var output = [{}];

for(let i in input){    
  for (let key in input[i]){
      if (output[0].hasOwnProperty(key)) {

    output[0][key]+=input[i][key];
    }else{
    output[0][key]=input[i][key];
    }
 }
}

console.log(JSON.stringify(output)); // errors out

但这并没有给我想要的结果，因为它无法对上面的分层 json 结构求和。

Answer 1

让我们从编写 merge 主函数开始：

function merge(x, y, fn) {

    if (isNotCompound(x) && isNotCompound(y)) {
        return fn(x, y);
    }

    if (isArray(x) && isArray(y)) {
        return mergeArray(x, y, fn);
    }

    if (isObject(x) && isObject(y)) {
        return mergeObject(x, y, fn);
    }

    throw new Error('the two input values are not of the same compound type');
} 

merge 函数相当于对其输入值x 和y 的类型进行调度。如果发现它们都是原始类型（即它们既不是数组也不是对象），它们将根据fn 函数进行合并。否则，将选择适当的辅助函数进行遍历。

因此，让我们实现调度所需的类型谓词：

   const isArray = x => Array.isArray(x);
   const isObject = x => Object.prototype.toString.call(x) === '[object Object]';
   const isNotCompound = x => !isArray(x) && !isObject(x);

现在是写mergeArray 和mergeObject 的问题。 mergeArray 的一种可能实现如下：

function mergeArray(xs, ys, fn) {
    if (xs.length !== ys.length) throw new Error('the two arrays must be of the same size');
    let r = [];
    for (let i = 0; i < xs.length; i++) {
      r.push(merge(xs[i], ys[i], fn));
    }  
    return r;
}

如图所示，mergeArray 要求两个数组大小相同。至于mergeObject，一种实现方式如下：

function mergeObject(obj1, obj2, fn) {
  let r = {};
  for (let key of Object.keys(obj1)) {
    r[key] = obj2[key] ? merge(obj1[key], obj2[key], fn) : obj1[key];
  }
  for (let key of Object.keys(obj2)) {
    if (r[key]) continue;
    r[key] = obj2[key];
  }
  return r;
}

值得注意的是，公共键的值被组合，而非共享属性直接传播到结果对象。

最后可以通过以下输入函数得到想要的合并策略：

const isNumber = x => typeof x === 'number';
const add = (x, y) => isNumber(x) && isNumber(y) ? x + y : (x || y);

如果两个输入的原始值都是数字，则返回它们的和，否则返回恰好定义的两者中的任何一个。

我们终于可以执行了：

console.log(JSON.stringify(merge(input1, input2, add)));

整个源代码如下。

const isArray = x => Array.isArray(x);
const isObject = x => Object.prototype.toString.call(x) === '[object Object]';
const isNotCompound = x => !isArray(x) && !isObject(x);

function merge(x, y, fn) {

  if (isNotCompound(x) && isNotCompound(y)) {
    return fn(x, y);
  }

  if (isArray(x) && isArray(y)) {
    return mergeArray(x, y, fn);
  }

  if (isObject(x) && isObject(y)) {
    return mergeObject(x, y, fn);
  }

  throw new Error('the two input values are not of the same compound type');
}; 

function mergeArray(xs, ys, fn) {
    if (xs.length !== ys.length) throw new Error('the two arrays must be of the same size');
    let r = [];
    for (let i = 0; i < xs.length; i++) {
      r.push(merge(xs[i], ys[i], fn));
    }  
    return r;
}

function mergeObject(obj1, obj2, fn) {
  let r = {};
  for (let key of Object.keys(obj1)) {
    r[key] = obj2[key] ? merge(obj1[key], obj2[key], fn) : obj1[key];
  }
  for (let key of Object.keys(obj2)) {
    if (r[key]) continue;
    r[key] = obj2[key];
  }
  return r;
}


let input1 = [{

    "201609": 5,
    "201610": 7,
    "201611": 9,
    "201612": 10,
    "FY17": 24,
    "metric": "metric1",
    "careerLevelGroups": [{
        "201609": 3,
        "201610": 6,
        "201611": 9,
        "201612": 8,
        "FY17": 18,
        "careerLevel": "Senior Managing Director",
        "careerLevels": [{
                "201609": 1,
                "201610": 2,
                "201611": 3,
                "201612": 5,
                "FY17": 6,
                "careerLevel": "CL1"
            },
            {
                "201609": 2,
                "201610": 4,
                "201611": 6,
                "201612": 9,
                "FY17": 12,
                "careerLevel": "CL2"
            }
        ]
    }]
}];

let input2 = [{

	"201609": 4,
	"201610": 8,
	"201611": 12,

	"FY17": 24,
	"metric": "metric1",
	"careerLevelGroups": [{
		"201609": 9,
		"201610": 2,
		"201611": 7,
		"FY17": 18,
		"careerLevel": "Senior Managing Director",
		"careerLevels": [{
			"201609": 3,
			"201610": 6,
			"201611": 9,
			"FY17": 18,
			"careerLevel": "CL1"
		}, {
			"201609": 7,
			"201610": 8,
			"201611": 9,
			"FY17": 24,
			"careerLevel": "CL2"
		}]
	}]
}];

const isNumber = x => typeof x === 'number';
const add = (x, y) => isNumber(x) && isNumber(y) ? x + y : (x || y);

console.log(JSON.stringify(merge(input1, input2, add)));

Answer 2

创建一个递归函数，并在其中使用forEach 迭代数组 流程是这样的，而不是循环 input1 和 input2 数组，循环其中一个，如果键的值是数字，则将其添加到另一个数组中相同键的值。如果值一个键是一个数组，然后用新的参数调用相同的递归函数

var input1 = [{

  "201609": 5,
  "201610": 7,
  "201611": 9,
  "201612": 10,
  "FY17": 24,
  "metric": "metric1",
  "careerLevelGroups": [{
    "201609": 3,
    "201610": 6,
    "201611": 9,
    "201612": 8,
    "FY17": 18,
    "careerLevel": "Senior Managing Director",
    "careerLevels": [{
        "201609": 1,
        "201610": 2,
        "201611": 3,
        "201612": 5,
        "FY17": 6,
        "careerLevel": "CL1"
      },
      {
        "201609": 2,
        "201610": 4,
        "201611": 6,
        "201612": 9,
        "FY17": 12,
        "careerLevel": "CL2"
      }
    ]
  }]
}]
var input2 = [{

  "201609": 4,
  "201610": 8,
  "201611": 12,

  "FY17": 24,
  "metric": "metric1",
  "careerLevelGroups": [{
    "201609": 9,
    "201610": 2,
    "201611": 7,
    "FY17": 18,
    "careerLevel": "Senior Managing Director",
    "careerLevels": [{
        "201609": 3,
        "201610": 6,
        "201611": 9,
        "FY17": 18,
        "careerLevel": "CL1"
      },
      {
        "201609": 7,
        "201610": 8,
        "201611": 9,
        "FY17": 24,
        "careerLevel": "CL2"
      }
    ]
  }]
}]
// A function which will take input2 and input1 array
function loopArray(arrayToBeLooped, addingArray) {
  // now looping over the array
  arrayToBeLooped.forEach(function(item, index) {
    // item is each object,here checking if the value of object key is array or number
    for (let keys in item) {
      // if number then find the same key from other array and add the value
      if (typeof item[keys] === 'number') {
        addingArray[index][keys] = addingArray[index][keys] + item[keys]
      }
      if (Array.isArray(item[keys])) {
        // if the type of value is another array for example
        //  careerLevelGroups & careerLevels then it is basically same
        // as looping over array input1 & input2
        // so calling the same loopArray function and passing different
        // parameter but the object remains same
        loopArray(arrayToBeLooped[index][keys], addingArray[index][keys])
      }
    }
  })
}
loopArray(input2, input1)
console.log(input1)