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

这是基于@JLavoie,使用lodash

let differences = function (newObj, oldObj) {
      return _.reduce(newObj, function (result, value, key) {
        if (!_.isEqual(value, oldObj[key])) {
          if (_.isArray(value)) {
            result[key] = []
            _.forEach(value, function (innerObjFrom1, index) {
              if (_.isNil(oldObj[key][index])) {
                result[key].push(innerObjFrom1)
              } else {
                let changes = differences(innerObjFrom1, oldObj[key][index])
                if (!_.isEmpty(changes)) {
                  result[key].push(changes)
                }
              }
            })
          } else if (_.isObject(value)) {
            result[key] = differences(value, oldObj[key])
          } else {
            result[key] = value
          }
        }
        return result
      }, {})
    }

https://jsfiddle.net/EmilianoBarboza/0g0sn3b9/8/

其他回答

如果你只需要键比较:

 _.reduce(a, function(result, value, key) {
     return b[key] === undefined ? key : []
  }, []);
var isEqual = function(f,s) {
  if (f === s) return true;

  if (Array.isArray(f)&&Array.isArray(s)) {
    return isEqual(f.sort(), s.sort());
  }
  if (_.isObject(f)) {
    return isEqual(f, s);
  }
  return _.isEqual(f, s);
};

一个简单而优雅的解决方案是使用_。isEqual,它执行深度比较:

Var a = {}; Var b = {}; A.prop1 = 2; A.prop2 = {prop3: 2}; B.prop1 = 2; B.prop2 = {prop3: 3}; console.log(_。isEqual (a, b));//如果不同则返回false < script src = " https://cdnjs.cloudflare.com/ajax/libs/lodash.js/4.17.4/lodash.min.js " > < /脚本>

然而,这个解决方案并没有显示哪个属性是不同的。

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 },
}));

对于无意中发现这条线索的人,这里有一个更完整的解决方案。它将比较两个对象,并给出所有属性的键,这些属性要么只存在于object1中,要么只存在于object2中,要么同时存在于object1和object2中,但值不同:

/*
 * Compare two objects by reducing an array of keys in obj1, having the
 * keys in obj2 as the intial value of the result. Key points:
 *
 * - All keys of obj2 are initially in the result.
 *
 * - If the loop finds a key (from obj1, remember) not in obj2, it adds
 *   it to the result.
 *
 * - If the loop finds a key that are both in obj1 and obj2, it compares
 *   the value. If it's the same value, the key is removed from the result.
 */
function getObjectDiff(obj1, obj2) {
    const diff = Object.keys(obj1).reduce((result, key) => {
        if (!obj2.hasOwnProperty(key)) {
            result.push(key);
        } else if (_.isEqual(obj1[key], obj2[key])) {
            const resultKeyIndex = result.indexOf(key);
            result.splice(resultKeyIndex, 1);
        }
        return result;
    }, Object.keys(obj2));

    return diff;
}

下面是一个输出示例:

// Test
let obj1 = {
    a: 1,
    b: 2,
    c: { foo: 1, bar: 2},
    d: { baz: 1, bat: 2 }
}

let obj2 = {
    b: 2, 
    c: { foo: 1, bar: 'monkey'}, 
    d: { baz: 1, bat: 2 }
    e: 1
}
getObjectDiff(obj1, obj2)
// ["c", "e", "a"]

如果你不关心嵌套对象并且想要跳过lodash,你可以替换_。isEqual用于正常的值比较,例如obj1[key] === obj2[key]。