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

我们需要在两个json更新之间获取delta，以跟踪数据库更新。也许其他人会觉得这很有用。

https://gist.github.com/jp6rt/7fcb6907e159d7851c8d59840b669e3d

const {
  isObject,
  isEqual,
  transform,
  has,
  merge,
} = require('lodash');
const assert = require('assert');

/**
 * Perform a symmetric comparison on JSON object.
 * @param {*} baseObj - The base object to be used for comparison against the withObj.
 * @param {*} withObj - The withObject parameter is used as the comparison on the base object.
 * @param {*} invert  - Because this is a symmetric comparison. Some values in the with object
 *                      that doesn't exist on the base will be lost in translation.
 *                      You can execute again the function again with the parameters interchanged.
 *                      However you will lose the reference if the value is from the base or with
 *                      object if you intended to do an assymetric comparison.
 *                      Setting this to true will do make sure the reference is not lost.
 * @returns           - The returned object will label the result of the comparison with the
 *                      value from base and with object.
 */
const diffSym = (baseObj, withObj, invert = false) => transform(baseObj, (result, value, key) => {
  if (isEqual(value, withObj[key])
    && has(withObj, key)) {
    return;
  }

  if (isObject(value)
    && isObject(withObj[key])
    && !Array.isArray(value)) {
    result[key] = diffSym(value, withObj[key], invert);
    return;
  }

  if (!invert) {
    result[key] = {
      base: value,
      with: withObj[key],
    };
    return;
  }

  if (invert) {
    result[key] = {
      base: withObj[key],
      with: value,
    };
  }
});

/**
 * Perform a assymmetric comparison on JSON object.
 * @param {*} baseObj - The base object to be used for comparison against the withObj.
 * @param {*} withObj - The withObject parameter is used as the comparison on the base object.
 * @returns           - The returned object will label the values with
 *                      reference to the base and with object.
 */
const diffJSON = (baseObj, withObj) => {
  // Deep clone the objects so we don't update the reference objects.
  const baseObjClone = JSON.parse(JSON.stringify(baseObj));
  const withObjClone = JSON.parse(JSON.stringify(withObj));

  const beforeDelta = diffSym(baseObjClone, withObjClone);
  const afterDelta = diffSym(withObjClone, baseObjClone, true);

  return merge(afterDelta, beforeDelta);
};

// By Example:

const beforeDataObj = {
  a: 1,
  c: { d: 2, f: 3 },
  g: 4,
  h: 5,
};
const afterDataObj = {
  a: 2,
  b: 3,
  c: { d: 1, e: 1 },
  h: 5,
};

const delta = diffJSON(beforeDataObj, afterDataObj);

// Assert expected result.
assert(isEqual(delta, {
  a: { base: 1, with: 2 },
  b: { base: undefined, with: 3 },
  c: {
    d: { base: 2, with: 1 },
    e: { base: undefined, with: 1 },
    f: { base: 3, with: undefined },
  },
  g: { base: 4, with: undefined },
}));

2020-08-20 17:40:12

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

深度比较使用模板的(嵌套)属性进行检查

function objetcsDeepEqualByTemplate(objectA, objectB, comparisonTemplate) {
  if (!objectA || !objectB) return false

  let areDifferent = false
  Object.keys(comparisonTemplate).some((key) => {
    if (typeof comparisonTemplate[key] === 'object') {
      areDifferent = !objetcsDeepEqualByTemplate(objectA[key], objectB[key], comparisonTemplate[key])
      return areDifferent
    } else if (comparisonTemplate[key] === true) {
      areDifferent = objectA[key] !== objectB[key]
      return areDifferent
    } else {
      return false
    }
  })

  return !areDifferent
}

const objA = { 
  a: 1,
  b: {
    a: 21,
    b: 22,
  },
  c: 3,
}

const objB = { 
  a: 1,
  b: {
    a: 21,
    b: 25,
  },
  c: true,
}

// template tells which props to compare
const comparisonTemplateA = {
  a: true,
  b: {
    a: true
  }
}
objetcsDeepEqualByTemplate(objA, objB, comparisonTemplateA)
// returns true

const comparisonTemplateB = {
  a: true,
  c: true
}
// returns false
objetcsDeepEqualByTemplate(objA, objB, comparisonTemplateB)

这将在控制台中工作。如果需要，可以添加数组支持

2017-09-01 15:50:13

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

如何做一个深层比较2个对象与lodash?

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