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

下面的方法将创建一个只更改字段的新对象

const findDiff = (obj1, obj2) => {
  const isNativeType1 = typeof obj1 !== "object";
  const isNativeType2 = typeof obj2 !== "object";
  if (isNativeType1 && isNativeType2) {
    return obj1 === obj2 ? null : obj2;
  }
  if (isNativeType1 && !isNativeType2) {
    return obj2;
  }
  if (!isNativeType1 && isNativeType2) {
    return obj2;
  }
  const isArray1 = Array.isArray(obj1);
  const isArray2 = Array.isArray(obj2);
  if (isArray1 && isArray2) {
    const firstLenght = obj1.length;
    const secondLenght = obj2.length;
    const hasSameLength = firstLenght === secondLenght;
    if (!hasSameLength) return obj2;
    let hasChange = false;
    for (let index = 0; index < obj1.length; index += 1) {
      const element1 = obj1[index];
      const element2 = obj2[index];
      const changed = findDiff(element1, element2);
      if (changed) {
        hasChange = true;
      }
    }
    return hasChange ? obj2 : null;
  }
  if (isArray1 || isArray2) return obj2;
  const keys1 = Object.keys(obj1);
  const keys2 = Object.keys(obj2);
  const hasSameKeys = keys1.length === keys2.length;
  if (!hasSameKeys) {
    const retObj = { ...obj2 };
    for (let index = 0; index < keys1.length; index += 1) {
      const key = keys1[index];
      if (!keys2.includes(key)) {
        retObj[key] = null;
        // eslint-disable-next-line no-continue
        continue;
      }
      delete retObj[key];
    }
    return retObj;
  }
  let hasChange = false;
  const retObj = {};
  for (let index = 0; index < keys1.length; index += 1) {
    const key = keys1[index];
    const element1 = obj1[key];
    const element2 = obj2[key];
    const changed = findDiff(element1, element2);
    if (changed) {
      hasChange = true;
    }
    if (changed) {
      retObj[key] = changed;
    }
  }
  return hasChange ? retObj : null;
};

console.log(
  JSON.stringify(findDiff(
    {
      a: 1,
      b: 2,
      c: {
        a: ['1', 'b', { a: 'b', c: false }, true],
      },
    },
    {
      a: 1,
      b: 2,
      c: {
        a: ['1','b', { a: 'b', c: true }, true],
      },
    }
  ), null, 2)
);

其他回答

我在这里跌跌撞撞地试图寻找一种方法来区分两个对象之间的区别。这是我使用Lodash的解决方案:

// Get updated values (including new values)
var updatedValuesIncl = _.omitBy(curr, (value, key) => _.isEqual(last[key], value));

// Get updated values (excluding new values)
var updatedValuesExcl = _.omitBy(curr, (value, key) => (!_.has(last, key) || _.isEqual(last[key], value)));

// Get old values (by using updated values)
var oldValues = Object.keys(updatedValuesIncl).reduce((acc, key) => { acc[key] = last[key]; return acc; }, {});

// Get newly added values
var newCreatedValues = _.omitBy(curr, (value, key) => _.has(last, key));

// Get removed values
var deletedValues = _.omitBy(last, (value, key) => _.has(curr, key));

// Then you can group them however you want with the result

Code snippet below: var last = { "authed": true, "inForeground": true, "goodConnection": false, "inExecutionMode": false, "online": true, "array": [1, 2, 3], "deep": { "nested": "value", }, "removed": "value", }; var curr = { "authed": true, "inForeground": true, "deep": { "nested": "changed", }, "array": [1, 2, 4], "goodConnection": true, "inExecutionMode": false, "online": false, "new": "value" }; // Get updated values (including new values) var updatedValuesIncl = _.omitBy(curr, (value, key) => _.isEqual(last[key], value)); // Get updated values (excluding new values) var updatedValuesExcl = _.omitBy(curr, (value, key) => (!_.has(last, key) || _.isEqual(last[key], value))); // Get old values (by using updated values) var oldValues = Object.keys(updatedValuesIncl).reduce((acc, key) => { acc[key] = last[key]; return acc; }, {}); // Get newly added values var newCreatedValues = _.omitBy(curr, (value, key) => _.has(last, key)); // Get removed values var deletedValues = _.omitBy(last, (value, key) => _.has(curr, key)); console.log('oldValues', JSON.stringify(oldValues)); console.log('updatedValuesIncl', JSON.stringify(updatedValuesIncl)); console.log('updatedValuesExcl', JSON.stringify(updatedValuesExcl)); console.log('newCreatedValues', JSON.stringify(newCreatedValues)); console.log('deletedValues', JSON.stringify(deletedValues)); <script src="https://cdnjs.cloudflare.com/ajax/libs/lodash.js/4.17.15/lodash.js"></script>

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;
}

另一个基于lodash的解决方案,它有点特定于我们想要查看对象更新的diff的情况:

const diff = return {
  old: _.pickBy(oldObject, (value, key) => { return !_.isEqual(value, newObject[key]); }),
  new: _.pickBy(newObject, (value, key) => { return !_.isEqual(oldObject[key], value); })
}

没有使用_。omitBy是因为性能影响。

var base = [
{"value": "01", "label": "Pendências"},
{"value": "02", "label": "Ambulatório"},
{"value": "03", "label": "Urgência"},
{"value": "04", "label": "Clínica Médica"},
{"value": "05", "label": "Revisão"},
{"value": "06", "label": "Imagens"},
];

var used = [
{"value": "01", "label": "Pendências"},
{"value": "02", "label": "Ambulatório"},
{"value": "03", "label": "Urgência"},
{"value": "04", "label": "Clínica Médica"},
];

function diff(obj1,obj2) {
        var temp = JSON.stringify(obj2.map((x)=> x.value));
    return obj1.filter((y)=> temp.indexOf(y.value)<0 && y);
}


var result = diff(base, used); 
console.clear();
console.log('RESULTADO');
console.log(result);

codeped

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'
}
*/