在嵌套的json对象中查找和更新

Question

我使用此代码从sJhonny's Question

中查找json对象所需的部分

数据样本

TestObj = {
    "Categories": [{
        "Products": [{
            "id": "a01",
            "name": "Pine",
            "description": "Short description of pine."
        },
        {
            "id": "a02",
            "name": "Birch",
            "description": "Short description of birch."
        },
        {
            "id": "a03",
            "name": "Poplar",
            "description": "Short description of poplar."
        }],
        "id": "A",
        "title": "Cheap",
        "description": "Short description of category A."
    },
    {
        "Product": [{
            "id": "b01",
            "name": "Maple",
            "description": "Short description of maple."
        },
        {
            "id": "b02",
            "name": "Oak",
            "description": "Short description of oak."
        },
        {
            "id": "b03",
            "name": "Bamboo",
            "description": "Short description of bamboo."
        }],
        "id": "B",
        "title": "Moderate",
        "description": "Short description of category B."
    }]
};

查找功能

function getObjects(obj, key, val) {
    var objects = [];
    for (var i in obj) {
        if (!obj.hasOwnProperty(i)) continue;
        if (typeof obj[i] == 'object') {
            objects = objects.concat(getObjects(obj[i], key, val));
        } else if (i == key && obj[key] == val) {
            objects.push(obj);
        }
    }
    return objects;
}

像这样使用：

getObjects(TestObj, 'id', 'A'); // Returns an array of matching objects

此代码用于从源中选择匹配的片段。但我想要的是用新值更新源对象并检索更新的源对象。

我想要像

这样的东西

getObjects(TestObj, 'id', 'A', 'B'); // Returns source with updated value. (ie id:'A' updated to id:'B' in the returned object)

我的代码

function getObjects(obj, key, val, newVal) {
    var newValue = newVal;
    var objects = [];
    for (var i in obj) {
        if (!obj.hasOwnProperty(i)) continue;
        if (typeof obj[i] == 'object') {
            objects = objects.concat(getObjects(obj[i], key, val));
        } else if (i == key && obj[key] == val) {
            obj[key] = 'qwe';
        }
    }
    return obj;
}

如果我提供obj[key] = 'qwe';，但是如果我将代码更改为obj[key] = newValue;，则将其更新为未定义。

为什么会这样？

Answer 1

您忘记在嵌套调用中传递newValue

function getObjects(obj, key, val, newVal) {
    var newValue = newVal;
    var objects = [];
    for (var i in obj) {
        if (!obj.hasOwnProperty(i)) continue;
        if (typeof obj[i] == 'object') {
            objects = objects.concat(getObjects(obj[i], key, val, newValue));
        } else if (i == key && obj[key] == val) {
            obj[key] = 'qwe';
        }
    }
    return obj;
}

Answer 2

这个？

function update(obj, key, newVal) {
    for(var i in obj) {
        if(typeof obj[i] == 'object') {
            update(obj[i], key, newVal));
        } else if(i === key) {
            obj[i] = newVal;
        }
    }
    return obj;
}

Answer 3

function getObjects(obj, key, val, newVal) {
  for (var i in obj) {
      if (!obj.hasOwnProperty(i)) continue;
      if (i == key && obj[key] == val) {
          obj[key] = newVal;
      }
  }
  return obj
}

这将使用newValue（newVal）

对找到的值进行就地更新

Answer 4

您可以尝试我的解决方案

const InsertOrUpdate = (dest, src) => {
    GetValue(dest, src, [])
}

const GetValue = (dest, src, keys) => {
    for (let key in src) {
        let srcValue = src[key]
        // Don't use push here
        // The concat() method does not change the existing arrays, but returns a new array, containing the values of the joined arrays
        let parentKeys = keys.concat(key)

        if (typeof (srcValue) === 'object') {
            GetValue(dest, srcValue, parentKeys)
        } else {
            SetValue(dest, parentKeys, srcValue)
        }
    }
}

const SetValue = (dest, keys, value) => {
    if (!keys.length || keys.length === 0) {
        return
    }

    let key = keys[0]
    let childKeys = keys.slice(1)

    // update
    // note: null is object
    if (dest[key] && typeof (dest[key]) === 'object') {
        SetValue(dest[key], childKeys, value)
    } else {
        // insert
        if (childKeys.length === 0) {
            dest[key] = value
        } else {
            // insert parent key & continue update
            dest[key] = {}
            SetValue(dest[key], childKeys, value)
        }
    }
}

Answer 5

我尝试使用上面选择的解决方案，但是它将使用相同的值更新每一行。因此，我添加了一种定义要更新的记录的方法，并且还提供了一种方法，一旦您经过它，就可以跟踪当前记录ID。

function getObjects(obj, rowId, key, val, newVal, rId) {
    var objects = [];        
    for (var i in obj) {   
        if(obj[i].id !== undefined) rId = obj[i].id; 
        if (!obj.hasOwnProperty(i)) continue;
        if (typeof obj[i] == 'object') {
            objects = objects.concat(this.updateObject(obj[i], rowId, key, val, newVal, rId));
        } else if (i == key && obj[key] == val) {
            if(rId == rowId) obj[key] = newVal;                      
        }
    }
    return obj;
}

Answer 6

看看object-scan。现在，我们将其用于大量数据处理。对我们来说，它使代码更易于维护，只需花一点时间就可以解决问题。这是您如何回答问题的方法

const objectScan = require('object-scan');

const update = (data, needle, from, to) => objectScan([needle], {
  abort: true,
  rtn: 'bool',
  filterFn: ({ value, parent, property }) => {
    if (value === from) {
      parent[property] = to;
      return true;
    }
    return false;
  }
})(data);

// -------------------------------

const TestObj = {"Categories":[{"Products":[{"id":"a01","name":"Pine","description":"Short description of pine."},{"id":"a02","name":"Birch","description":"Short description of birch."},{"id":"a03","name":"Poplar","description":"Short description of poplar."}],"id":"A","title":"Cheap","description":"Short description of category A."},{"Product":[{"id":"b01","name":"Maple","description":"Short description of maple."},{"id":"b02","name":"Oak","description":"Short description of oak."},{"id":"b03","name":"Bamboo","description":"Short description of bamboo."}],"id":"B","title":"Moderate","description":"Short description of category B."}]};

console.log(update(TestObj, '**.id', 'A', 'B'));
// => true
console.log(JSON.stringify(TestObj));
// => {"Categories":[{"Products":[{"id":"a01","name":"Pine","description":"Short description of pine."},{"id":"a02","name":"Birch","description":"Short description of birch."},{"id":"a03","name":"Poplar","description":"Short description of poplar."}],"id":"B","title":"Cheap","description":"Short description of category A."},{"Product":[{"id":"b01","name":"Maple","description":"Short description of maple."},{"id":"b02","name":"Oak","description":"Short description of oak."},{"id":"b03","name":"Bamboo","description":"Short description of bamboo."}],"id":"B","title":"Moderate","description":"Short description of category B."}]}