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

我已经使用这段代码来完成你所描述的任务:

function mergeRecursive(obj1, obj2) {
    for (var p in obj2) {
        try {
            if(obj2[p].constructor == Object) {
                obj1[p] = mergeRecursive(obj1[p], obj2[p]);
            }
            // Property in destination object set; update its value.
            else if (Ext.isArray(obj2[p])) {
                // obj1[p] = [];
                if (obj2[p].length < 1) {
                    obj1[p] = obj2[p];
                }
                else {
                    obj1[p] = mergeRecursive(obj1[p], obj2[p]);
                }

            }else{
                obj1[p] = obj2[p];
            }
        } catch (e) {
            // Property in destination object not set; create it and set its value.
            obj1[p] = obj2[p];
        }
    }
    return obj1;
}

这将为您提供一个新对象,该对象将合并窗体中的旧对象和新对象之间的所有更改

其他回答

我已经使用这段代码来完成你所描述的任务:

function mergeRecursive(obj1, obj2) {
    for (var p in obj2) {
        try {
            if(obj2[p].constructor == Object) {
                obj1[p] = mergeRecursive(obj1[p], obj2[p]);
            }
            // Property in destination object set; update its value.
            else if (Ext.isArray(obj2[p])) {
                // obj1[p] = [];
                if (obj2[p].length < 1) {
                    obj1[p] = obj2[p];
                }
                else {
                    obj1[p] = mergeRecursive(obj1[p], obj2[p]);
                }

            }else{
                obj1[p] = obj2[p];
            }
        } catch (e) {
            // Property in destination object not set; create it and set its value.
            obj1[p] = obj2[p];
        }
    }
    return obj1;
}

这将为您提供一个新对象,该对象将合并窗体中的旧对象和新对象之间的所有更改

这是在gisthub上找到的一个修改版本。

isNullBlankOrUndefined = function (o) {
    return (typeof o === "undefined" || o == null || o === "");
}

/**
 * Deep diff between two object, using lodash
 * @param  {Object} object Object compared
 * @param  {Object} base   Object to compare with
 * @param  {Object} ignoreBlanks will not include properties whose value is null, undefined, etc.
 * @return {Object}        Return a new object who represent the diff
 */
objectDifference = function (object, base, ignoreBlanks = false) {
    if (!lodash.isObject(object) || lodash.isDate(object)) return object            // special case dates
    return lodash.transform(object, (result, value, key) => {
        if (!lodash.isEqual(value, base[key])) {
            if (ignoreBlanks && du.isNullBlankOrUndefined(value) && isNullBlankOrUndefined( base[key])) return;
            result[key] = lodash.isObject(value) && lodash.isObject(base[key]) ? objectDifference(value, base[key]) : value;
        }
    });
}

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'},
}

我修改了@sbgoran的答案,这样得到的diff对象只包括改变的值,省略了相同的值。此外,它同时显示原始值和更新后的值。

var deepDiffMapper = function () {
    return {
        VALUE_CREATED: 'created',
        VALUE_UPDATED: 'updated',
        VALUE_DELETED: 'deleted',
        VALUE_UNCHANGED: '---',
        map: function (obj1, obj2) {
            if (this.isFunction(obj1) || this.isFunction(obj2)) {
                throw 'Invalid argument. Function given, object expected.';
            }
            if (this.isValue(obj1) || this.isValue(obj2)) {
                let returnObj = {
                    type: this.compareValues(obj1, obj2),
                    original: obj1,
                    updated: obj2,
                };
                if (returnObj.type != this.VALUE_UNCHANGED) {
                    return returnObj;
                }
                return undefined;
            }

            var diff = {};
            let foundKeys = {};
            for (var key in obj1) {
                if (this.isFunction(obj1[key])) {
                    continue;
                }

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

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

                let mapValue = this.map(undefined, obj2[key]);
                if (mapValue) {
                    diff[key] = mapValue;
                }
            }

            //2020-06-13: object length code copied from https://stackoverflow.com/a/13190981/2336212
            if (Object.keys(diff).length > 0) {
                return diff;
            }
            return undefined;
        },
        compareValues: function (value1, value2) {
            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) {
            return Object.prototype.toString.call(x) === '[object Function]';
        },
        isArray: function (x) {
            return Object.prototype.toString.call(x) === '[object Array]';
        },
        isDate: function (x) {
            return Object.prototype.toString.call(x) === '[object Date]';
        },
        isObject: function (x) {
            return Object.prototype.toString.call(x) === '[object Object]';
        },
        isValue: function (x) {
            return !this.isObject(x) && !this.isArray(x);
        }
    }
}();

使用下划线,一个简单的差异:

var o1 = {a: 1, b: 2, c: 2},
    o2 = {a: 2, b: 1, c: 2};

_.omit(o1, function(v,k) { return o2[k] === v; })

o1中对应但o2值不同的部分的结果:

{a: 1, b: 2}

如果是深差的话就不一样了

function diff(a,b) {
    var r = {};
    _.each(a, function(v,k) {
        if(b[k] === v) return;
        // but what if it returns an empty object? still attach?
        r[k] = _.isObject(v)
                ? _.diff(v, b[k])
                : v
            ;
        });
    return r;
}

正如@Juhana在评论中指出的那样,上面只是一个diff a- >b,并且不可逆(这意味着b中的额外属性将被忽略)。用a——>b——>a代替:

(function(_) {
  function deepDiff(a, b, r) {
    _.each(a, function(v, k) {
      // already checked this or equal...
      if (r.hasOwnProperty(k) || b[k] === v) return;
      // but what if it returns an empty object? still attach?
      r[k] = _.isObject(v) ? _.diff(v, b[k]) : v;
    });
  }

  /* the function */
  _.mixin({
    diff: function(a, b) {
      var r = {};
      deepDiff(a, b, r);
      deepDiff(b, a, r);
      return r;
    }
  });
})(_.noConflict());

完整的示例+tests+mixins请参见http://jsfiddle.net/drzaus/9g5qoxwj/