我有两个对象:oldObj和newObj。

oldObj中的数据用于填充表单,而newObj是用户更改该表单中的数据并提交的结果。

这两个物体都很深。它们具有对象或对象数组等属性-它们可以有n层深,因此diff算法需要递归。

现在我不仅需要弄清楚从oldObj到newObj更改了什么(如添加/更新/删除),而且还需要知道如何最好地表示它。

到目前为止,我的想法只是构建一个通用的deepdiffbetweenobjects方法,该方法将返回窗体上的对象{add:{…},upd:{…},del:{…但我转念一想:以前一定有人需要它。

所以…有没有人知道一个库或一段代码可以做到这一点,并且可能有更好的方式来表示差异(以一种仍然是JSON可序列化的方式)?

更新:

我想到了一个更好的方法来表示更新的数据,通过使用与newObj相同的对象结构,但将所有属性值转换为窗体上的对象:

{type: '<update|create|delete>', data: <propertyValue>}

如果newObj。prop1 = 'new value'和oldObj。prop1 = 'old value'它将设置returnbj。Prop1 = {type: 'update', data: 'new value'}

更新2:

当我们处理数组的属性时,它会变得非常麻烦,因为数组[1,2,3]应该被计算为等于[2,3,1],这对于基于值的类型的数组(如string, int和bool)来说足够简单,但是当涉及到引用类型的数组(如对象和数组)时就很难处理了。

数组的示例应该是相等的:

[1,[{c: 1},2,3],{a:'hey'}] and [{a:'hey'},1,[3,{c: 1},2]]

不仅要检查这种类型的深度值相等相当复杂,而且要找出一种表示可能发生的变化的好方法。


当前回答

如今,有相当多的模块可用于此。我最近写了一个模块来做到这一点,因为我不满意我发现的大量不同的模块。它被称为odiff: https://github.com/Tixit/odiff。我还列出了一些最流行的模块,以及为什么它们不能在odiff的自述中被接受,如果odiff没有你想要的属性,你可以查看一下。这里有一个例子:

var a = [{a:1,b:2,c:3},              {x:1,y: 2, z:3},              {w:9,q:8,r:7}]
var b = [{a:1,b:2,c:3},{t:4,y:5,u:6},{x:1,y:'3',z:3},{t:9,y:9,u:9},{w:9,q:8,r:7}]

var diffs = odiff(a,b)

/* diffs now contains:
[{type: 'add', path:[], index: 2, vals: [{t:9,y:9,u:9}]},
 {type: 'set', path:[1,'y'], val: '3'},
 {type: 'add', path:[], index: 1, vals: [{t:4,y:5,u:6}]}
]
*/

其他回答

我采用@sbgoran上面的答案,并根据我的情况修改了它,以将数组视为集合(即顺序对于diff不重要)

const deepDiffMapper = function () {
return {
  VALUE_CREATED: "created",
  VALUE_UPDATED: "updated",
  VALUE_DELETED: "deleted",
  VALUE_UNCHANGED: "unchanged",
  map: function(obj1: any, obj2: any) {
    if (this.isFunction(obj1) || this.isFunction(obj2)) {
      throw "Invalid argument. Function given, object expected.";
    }
    if (this.isValue(obj1) || this.isValue(obj2)) {
      return {
        type: this.compareValues(obj1, obj2),
        data: obj2 === undefined ? obj1 : obj2
      };
    }

    if (this.isArray(obj1) || this.isArray(obj2)) {
      return {
        type: this.compareArrays(obj1, obj2),
        data: this.getArrayDiffData(obj1, obj2)
      };
    }

    const diff: any = {};
    for (const key in obj1) {

      if (this.isFunction(obj1[key])) {
        continue;
      }

      let value2 = undefined;
      if (obj2[key] !== undefined) {
        value2 = obj2[key];
      }

      diff[key] = this.map(obj1[key], value2);
    }
    for (const key in obj2) {
      if (this.isFunction(obj2[key]) || diff[key] !== undefined) {
        continue;
      }

      diff[key] = this.map(undefined, obj2[key]);
    }

    return diff;

  },

  getArrayDiffData: function(arr1: Array<any>, arr2: Array<any>) {
    const set1 = new Set(arr1);
    const set2 = new Set(arr2);

    if (arr1 === undefined || arr2 === undefined) {
       return arr1 === undefined ? arr1 : arr2;
    }
    const deleted = [...arr1].filter(x => !set2.has(x));

    const added = [...arr2].filter(x => !set1.has(x));

    return {
      added, deleted
    };

  },

  compareArrays: function(arr1: Array<any>, arr2: Array<any>) {
    const set1 = new Set(arr1);
    const set2 = new Set(arr2);
    if (_.isEqual(_.sortBy(arr1), _.sortBy(arr2))) {
      return this.VALUE_UNCHANGED;
    }
    if (arr1 === undefined) {
      return this.VALUE_CREATED;
    }
    if (arr2 === undefined) {
      return this.VALUE_DELETED;
    }
    return this.VALUE_UPDATED;
  },
  compareValues: function (value1: any, value2: any) {
    if (value1 === value2) {
      return this.VALUE_UNCHANGED;
    }
    if (this.isDate(value1) && this.isDate(value2) && value1.getTime() === value2.getTime()) {
      return this.VALUE_UNCHANGED;
    }
    if (value1 === undefined) {
      return this.VALUE_CREATED;
    }
    if (value2 === undefined) {
      return this.VALUE_DELETED;
    }
    return this.VALUE_UPDATED;
  },
  isFunction: function (x: any) {
    return Object.prototype.toString.call(x) === "[object Function]";
  },
  isArray: function (x: any) {
    return Object.prototype.toString.call(x) === "[object Array]";
  },
  isDate: function (x: any) {
    return Object.prototype.toString.call(x) === "[object Date]";
  },
  isObject: function (x: any) {
    return Object.prototype.toString.call(x) === "[object Object]";
  },
  isValue: function (x: any) {
    return !this.isObject(x) && !this.isArray(x);
  }
 };
}();

我知道我迟到了,但我需要类似的东西,上面的答案没有帮助。

我使用了Angular的$watch函数来检测变量的变化。我不仅需要知道变量上的属性是否发生了变化,而且还需要确保发生变化的属性不是一个临时的计算字段。换句话说,我想忽略某些属性。

代码如下:

function diff(obj1,obj2,exclude) {
        var r = {};
    
    if (!exclude)   exclude = [];
    
    for (var prop in obj1) {
      if (obj1.hasOwnProperty(prop) && prop != '__proto__') {
            if (exclude.indexOf(obj1[prop]) == -1) {

            // check if obj2 has prop
            if (!obj2.hasOwnProperty(prop)) r[prop] = obj1[prop];

            // check if prop is object and 
            // NOT a JavaScript engine object (i.e. __proto__), if so, recursive diff
            else if (obj1[prop] === Object(obj1[prop])) {
              var difference = diff(obj1[prop], obj2[prop]);
              if (Object.keys(difference).length > 0) r[prop] = difference;
            }

            // check if obj1 and obj2 are equal
            else if (obj1[prop] !== obj2[prop]) {
                if (obj1[prop] === undefined)
                r[prop] = 'undefined';
                if (obj1[prop] === null)
                r[prop] = null;
              else if (typeof obj1[prop] === 'function')
                r[prop] = 'function';
              else if (typeof obj1[prop] === 'object')  
                r[prop] = 'object';
              else
                  r[prop] = obj1[prop];
            }
          }
       }
       
    }
    
    return r;
}

https://jsfiddle.net/rv01x6jo/


下面是如何使用它:

// To only return the difference
var difference = diff(newValue, oldValue);  

// To exclude certain properties
var difference = diff(newValue, oldValue, [newValue.prop1, newValue.prop2, newValue.prop3]);

希望这能帮助到一些人。

这里有一个解决方案:

TypeScript(但很容易转换为JavaScript) 没有lib依赖项 泛型的,不关心检查对象类型(除了对象类型) 支持值为undefined的属性 深度不(默认)

首先,我们定义比较结果接口:

export interface ObjectDiff {
  added: {} | ObjectDiff;
  updated: {
    [propName: string]: Update | ObjectDiff;
  };
  removed: {} | ObjectDiff;
  unchanged: {} | ObjectDiff;
}

对于change的特殊情况,我们想知道什么是旧值和新值:

export interface Update {
  oldValue: any;
  newValue: any;
}

然后我们可以提供只有两个循环的diff函数(如果deep为真,则具有递归性):

export class ObjectUtils {
  /**
   * @return if obj is an Object, including an Array.
   */
  static isObject(obj: any) {
    return obj !== null && typeof obj === 'object';
  }

  /**
   * @param oldObj The previous Object or Array.
   * @param newObj The new Object or Array.
   * @param deep If the comparison must be performed deeper than 1st-level properties.
   * @return A difference summary between the two objects.
   */
  static diff(oldObj: {}, newObj: {}, deep = false): ObjectDiff {
    const added = {};
    const updated = {};
    const removed = {};
    const unchanged = {};
    for (const oldProp in oldObj) {
      if (oldObj.hasOwnProperty(oldProp)) {
        const newPropValue = newObj[oldProp];
        const oldPropValue = oldObj[oldProp];
        if (newObj.hasOwnProperty(oldProp)) {
          if (newPropValue === oldPropValue) {
            unchanged[oldProp] = oldPropValue;
          } else {
            updated[oldProp] = deep && this.isObject(oldPropValue) && this.isObject(newPropValue) ? this.diff(oldPropValue, newPropValue, deep) : {newValue: newPropValue};
          }
        } else {
          removed[oldProp] = oldPropValue;
        }
      }
    }
    for (const newProp in newObj) {
      if (newObj.hasOwnProperty(newProp)) {
        const oldPropValue = oldObj[newProp];
        const newPropValue = newObj[newProp];
        if (oldObj.hasOwnProperty(newProp)) {
          if (oldPropValue !== newPropValue) {
            if (!deep || !this.isObject(oldPropValue)) {
              updated[newProp].oldValue = oldPropValue;
            }
          }
        } else {
          added[newProp] = newPropValue;
        }
      }
    }
    return {added, updated, removed, unchanged};
  }
}

例如,调用:

ObjectUtils.diff(
  {
    a: 'a', 
    b: 'b', 
    c: 'c', 
    arr: ['A', 'B'], 
    obj: {p1: 'p1', p2: 'p2'}
  },
  {
    b: 'x', 
    c: 'c', 
    arr: ['B', 'C'], 
    obj: {p2: 'p2', p3: 'p3'}, 
    d: 'd'
  },
);

将返回:

{
  added: {d: 'd'},
  updated: {
    b: {oldValue: 'b', newValue: 'x'},
    arr: {oldValue: ['A', 'B'], newValue: ['B', 'C']},
    obj: {oldValue: {p1: 'p1', p2: 'p2'}, newValue: {p2: 'p2', p3: 'p3'}}
  },
  removed: {a: 'a'},
  unchanged: {c: 'c'},
}

对deep third参数调用同样的方法将返回:

{
  added: {d: 'd'},
  updated: {
    b: {oldValue: 'b', newValue: 'x'},
    arr: {
      added: {},
      removed: {},
      unchanged: {},
      updated: {
        0: {oldValue: 'A', newValue: 'B'},
        1: {oldValue: 'B', newValue: 'C', }
      }
    },
    obj: {
      added: {p3: 'p3'},
      removed: {p1: 'p1'},
      unchanged: {p2: 'p2'},
      updated: {}
    }
  },
  removed: {a: 'a'},
  unchanged: {c: 'c'},
}
const diff = require("deep-object-diff").diff;
let differences = diff(obj2, obj1);

有一个每周下载量超过50万的npm模块:https://www.npmjs.com/package/deep-object-diff

我喜欢对象式的差异表示-特别是当它形成时,很容易看到结构。

const diff = require("deep-object-diff").diff;

const lhs = {
  foo: {
    bar: {
      a: ['a', 'b'],
      b: 2,
      c: ['x', 'y'],
      e: 100 // deleted
    }
  },
  buzz: 'world'
};

const rhs = {
  foo: {
    bar: {
      a: ['a'], // index 1 ('b')  deleted
      b: 2, // unchanged
      c: ['x', 'y', 'z'], // 'z' added
      d: 'Hello, world!' // added
    }
  },
  buzz: 'fizz' // updated
};

console.log(diff(lhs, rhs)); // =>
/*
{
  foo: {
    bar: {
      a: {
        '1': undefined
      },
      c: {
        '2': 'z'
      },
      d: 'Hello, world!',
      e: undefined
    }
  },
  buzz: 'fizz'
}
*/

2022年更新:

我想出了一个非常简单的算法来解决大多数边缘情况:

使物体变平 简单地比较两个扁平对象并创建一个扁平的diff对象 平展diff对象

如果你保存了被压平的物体,你就可以重复使用它,并在你真正需要的时候进行“反压平…”

let oldObject = {var1:'value1', var2:{ var1:'value1', var2:'value2'},var3:'value3'};
let newObject = {var2:{ var1:'value11', var3:'value3'},var3:'value3'};

let flatOldObject = flattenObject(oldObject)
/*
{
 'var1':'value1',
 'var2.var1':'value1',
 'var2.var2':'value2',
 'var3':'value3' 
}
*/
let flatNewObject = flattenObject(newObject)
/*
{
 'var2.var1':'value11',
 'var2.var3':'value3',
 'var3':'value3'
}
*/
let flatDiff = diffFlatten(flatOldObject, flatNewObject)
let [updated,removed] = flatDiff
/*
updated = {
 'var2.var1':'value11',
 'var2.var3':'value3'
}
removed = {
'var1':'value1'
}
*/

当然,您可以为这些步骤提供您的实现。但我的想法是:

实现

function flattenObject(obj) {
 const object = Object.create(null);
 const path = [];
 const isObject = (value) => Object(value) === value;

 function dig(obj) {
  for (let [key, value] of Object.entries(obj)) {
    path.push(key);
    if (isObject(value)) dig(value);
    else object[path.join('.')] = value;
    path.pop();
  }
 }

 dig(obj);
 return object;
}
function diffFlatten(oldFlat, newFlat) {
    const updated = Object.assign({}, oldFlat);
    const removed = Object.assign({}, newFlat);

    /**delete the unUpdated keys*/
    for (let key in newFlat) {
        if (newFlat[key] === oldFlat[key]) {
             delete updated[key];
             delete removed[key];
        }
    }

    return [updated, removed];

}
function unflatenObject(flattenObject) {
    const unFlatten = Object.create(null);
    for (let [stringKeys, value] of Object.entries(flattenObject)) {
        let chain = stringKeys.split('.')
        let object = unFlatten

        for (let [i, key] of chain.slice(0, -1).entries()) {
            if (!object[key]) {
                let needArray = Number.isInteger(Number(chain[+i + 1]))
                object[key] = needArray ? [] : Object.create(null)
            }
            object = object[key];
        }
        let lastkey = chain.pop();
        object[lastkey] = value;
    }
    return unFlatten;
}