如何做一个深层比较2个对象与lodash?

我有2个不同的嵌套对象，我需要知道它们是否在其中一个嵌套属性中有不同。

var a = {};
var b = {};

a.prop1 = 2;
a.prop2 = { prop3: 2 };

b.prop1 = 2;
b.prop2 = { prop3: 3 };

对象可以更复杂，有更多嵌套的属性。但这是一个很好的例子。我可以选择使用递归函数或lodash的东西…

当前回答

这是我对这个问题的解决办法

const _ = require('lodash');

var objects = [{ 'x': 1, 'y': 2, 'z':3, a:{b:1, c:2, d:{n:0}}, p:[1, 2, 3]  }, { 'x': 2, 'y': 1, z:3, a:{b:2, c:2,d:{n:1}}, p:[1,3], m:3  }];

const diffFn=(a,b, path='')=>_.reduce(a, function(result, value, key) {

    if(_.isObjectLike(value)){
      if(_.isEqual(value, b[key])){
        return result;
      }else{

return result.concat(diffFn(value, b[key], path?(`${path}.${key}`):key))
      }
    }else{
return _.isEqual(value, b[key]) ?
        result : result.concat(path?(`${path}.${key}`):key);
    }
    
}, []);

const diffKeys1=diffFn(objects[0], objects[1])
const diffKeys2=diffFn(objects[1], objects[0])
const diffKeys=_.union(diffKeys1, diffKeys2)
const res={};

_.forEach(diffKeys, (key)=>_.assign(res, {[key]:{ old: _.get(objects[0], key), new:_.get(objects[1], key)} }))

res
/*
Returns
{
  x: { old: 1, new: 2 },
  y: { old: 2, new: 1 },
  'a.b': { old: 1, new: 2 },
  'a.d.n': { old: 0, new: 1 },
  'p.1': { old: 2, new: 3 },
  'p.2': { old: 3, new: undefined },
  m: { old: undefined, new: 3 }
}
*/

2020-11-03 15:52:09

其他回答

作为对亚当·博杜赫的回答的补充，这个问题考虑到了性质的差异

const differenceOfKeys = (...objects) =>
  _.difference(...objects.map(obj => Object.keys(obj)));
const differenceObj = (a, b) => 
  _.reduce(a, (result, value, key) => (
    _.isEqual(value, b[key]) ? result : [...result, key]
  ), differenceOfKeys(b, a));

2016-10-01 23:12:09

基于Adam Boduch的回答，我写了这个函数，它在最深层的意义上比较两个对象，返回具有不同值的路径以及从一个或另一个对象中缺失的路径。

代码的编写并没有考虑到效率，在这方面的改进是非常受欢迎的，但这里是基本形式:

var compare = function (a, b) {

  var result = {
    different: [],
    missing_from_first: [],
    missing_from_second: []
  };

  _.reduce(a, function (result, value, key) {
    if (b.hasOwnProperty(key)) {
      if (_.isEqual(value, b[key])) {
        return result;
      } else {
        if (typeof (a[key]) != typeof ({}) || typeof (b[key]) != typeof ({})) {
          //dead end.
          result.different.push(key);
          return result;
        } else {
          var deeper = compare(a[key], b[key]);
          result.different = result.different.concat(_.map(deeper.different, (sub_path) => {
            return key + "." + sub_path;
          }));

          result.missing_from_second = result.missing_from_second.concat(_.map(deeper.missing_from_second, (sub_path) => {
            return key + "." + sub_path;
          }));

          result.missing_from_first = result.missing_from_first.concat(_.map(deeper.missing_from_first, (sub_path) => {
            return key + "." + sub_path;
          }));
          return result;
        }
      }
    } else {
      result.missing_from_second.push(key);
      return result;
    }
  }, result);

  _.reduce(b, function (result, value, key) {
    if (a.hasOwnProperty(key)) {
      return result;
    } else {
      result.missing_from_first.push(key);
      return result;
    }
  }, result);

  return result;
}

您可以使用以下代码段(建议以全页模式运行)尝试代码:

2017-01-02 18:28:26

As it was asked, here's a recursive object comparison function. And a bit more. Assuming that primary use of such function is object inspection, I have something to say. Complete deep comparison is a bad idea when some differences are irrelevant. For example, blind deep comparison in TDD assertions makes tests unnecessary brittle. For that reason, I'd like to introduce a much more valuable partial diff. It is a recursive analogue of a previous contribution to this thread. It ignores keys not present in a

var bdiff = (a, b) =>
    _.reduce(a, (res, val, key) =>
        res.concat((_.isPlainObject(val) || _.isArray(val)) && b
            ? bdiff(val, b[key]).map(x => key + '.' + x) 
            : (!b || val != b[key] ? [key] : [])),
        []);

BDiff允许检查期望值，同时容忍其他属性，这正是您想要的自动检查。这允许构建各种高级断言。例如:

var diff = bdiff(expected, actual);
// all expected properties match
console.assert(diff.length == 0, "Objects differ", diff, expected, actual);
// controlled inequality
console.assert(diff.length < 3, "Too many differences", diff, expected, actual);

回到完整的解决方案。使用bdiff构建一个完整的传统diff是很简单的:

function diff(a, b) {
    var u = bdiff(a, b), v = bdiff(b, a);
    return u.filter(x=>!v.includes(x)).map(x=>' < ' + x)
    .concat(u.filter(x=>v.includes(x)).map(x=>' | ' + x))
    .concat(v.filter(x=>!u.includes(x)).map(x=>' > ' + x));
};

在两个复杂对象上运行上述函数将输出类似于下面的内容:

 [
  " < components.0.components.1.components.1.isNew",
  " < components.0.cryptoKey",
  " | components.0.components.2.components.2.components.2.FFT.min",
  " | components.0.components.2.components.2.components.2.FFT.max",
  " > components.0.components.1.components.1.merkleTree",
  " > components.0.components.2.components.2.components.2.merkleTree",
  " > components.0.components.3.FFTResult"
 ]

最后，为了了解值之间的差异，我们可能需要直接eval() diff输出。为此，我们需要一个更丑的bdiff版本，输出语法正确的路径:

// provides syntactically correct output
var bdiff = (a, b) =>
    _.reduce(a, (res, val, key) =>
        res.concat((_.isPlainObject(val) || _.isArray(val)) && b
            ? bdiff(val, b[key]).map(x => 
                key + (key.trim ? '':']') + (x.search(/^\d/)? '.':'[') + x)
            : (!b || val != b[key] ? [key + (key.trim ? '':']')] : [])),
        []);

// now we can eval output of the diff fuction that we left unchanged
diff(a, b).filter(x=>x[1] == '|').map(x=>[x].concat([a, b].map(y=>((z) =>eval('z.' + x.substr(3))).call(this, y)))));

这将输出类似于下面的内容:

[" | components[0].components[2].components[2].components[2].FFT.min", 0, 3]
[" | components[0].components[2].components[2].components[2].FFT.max", 100, 50]

“一族”许可

2018-05-10 17:11:58

以Sridhar Gudimela的回答为基础，下面以一种使用TypeScript的方式进行了更新:

///  U T I L S

interface LooseObjectInterface {
  [key: string]: any;
};

type inputOptions = LooseObjectInterface | any[];



///  E X P O R T

export const objectCompare = (objectA: inputOptions, objectB: inputOptions): LooseObjectInterface => {
  let diffObj: LooseObjectInterface = {};

  switch(true) {
    case (Array.isArray(objectA)):
      objectA.forEach((elem: any, index: number) => {
        if (!Array.isArray(diffObj))
          diffObj = [];

        diffObj[index] = objectCompare(elem, (objectB || [])[index]);
      });

      break;

    case (objectA !== null && typeof objectA === "object"):
      Object.keys(objectA).forEach((key: any) => {
        if (Array.isArray(objectA[key])) {
          let arr = objectCompare(objectA[key], objectB[key]);

          if (!Array.isArray(arr))
            arr = [];

          arr.forEach((elem: any, index: number) => {
            if (!Array.isArray(diffObj[key]))
              diffObj[key] = [];

            diffObj[key][index] = elem;
          });
        } else if (typeof objectA[key] === "object")
          diffObj[key] = objectCompare(objectA[key], objectB[key]);
        else if (objectA[key] !== (objectB || {})[key])
          diffObj[key] = objectA[key];
        else if (objectA[key] === (objectB || {})[key])
          delete objectA[key];
      });

      break;

    default:
      break;
  }

  Object.keys(diffObj).forEach((key: any) => {
    if (typeof diffObj[key] === "object" && JSON.stringify(diffObj[key]) === "{}")
      delete diffObj[key];
  });

  return diffObj;
};

编辑:我最初的回答使用了Flow，因此被否决了(我猜，或者可能是因为我的回答没有使用Lodash……)然而，有一个类似问题的答案也无妨)。

2019-10-31 22:32:21

我需要知道它们的某个嵌套属性是否不同

其他答案为这个问题提供了可能令人满意的解决方案，但它非常困难和常见，似乎有一个非常受欢迎的包来帮助解决这个问题。

要使用这个包，你需要npm i deep-object-diff，然后:

const { diff } = require('deep-object-diff');
var a = {};
var b = {};

a.prop1 = 2;
a.prop2 = { prop3: 2 };

b.prop1 = 2;
b.prop2 = { prop3: 3 };

if (!_.isEqual(a, b)) {
  const abDiff = diff(a, b);
  console.log(abDiff);
  /*
  {
    prop2: {
      prop3: 3
    }
  }
  */
}

// or alternatively
const abDiff = diff(a, b);
if(!_.isEmpty(abDiff)) {
  // if a diff exists then they aren't deeply equal
  // perform needed actions with diff...
}

下面是一个更详细的案例，直接从他们的文档中删除属性:

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'
}
*/

有关实现细节和其他使用信息，请参阅该repo。

2020-08-04 17:52:52

如何做一个深层比较2个对象与lodash?

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