How can I check that two objects have the same set of property names

Question

I am using node  mocha  and chai for my application  I want to test that my returned results data property is the same  type of object  as one of my model objects  Very similar to chai s instance   I just want to confirm that the two objects have the same sets of property names  I am specifically not interested in the actual values of the properties   Let s say I have the model Person like below   I want to check that my results data has all the same properties as the expected model does   So in this case  Person which has a firstName and lastName   So if results data lastName and results data firstName both exist  then it should return true   If either one doesn t exist  it should return false   A bonus would be if results data has any additional properties like results data surname  then it would return false because surname doesn t exist in Person   This model  function Person data      var self   this    self firstName    unknown     self lastName    unknown      if  typeof data     undefined          self firstName   data firstName       self lastName   data lastName

User · Answer

If you are using underscoreJs then you can simply use _.isEqual function and it compares all keys and values at each and every level of hierarchy like below example.

var object = {"status":"inserted","id":"5799acb792b0525e05ba074c","data":{"workout":[{"set":[{"setNo":1,"exercises":[{"name":"hjkh","type":"Reps","category":"Cardio","set":{"reps":5}}],"isLastSet":false,"index":0,"isStart":true,"startDuration":1469689001989,"isEnd":true,"endDuration":1469689003323,"speed":"00:00:01"}],"setType":"Set","isSuper":false,"index":0}],"time":"2016-07-28T06:56:52.800Z"}};

var object1 = {"status":"inserted","id":"5799acb792b0525e05ba074c","data":{"workout":[{"set":[{"setNo":1,"exercises":[{"name":"hjkh","type":"Reps","category":"Cardio","set":{"reps":5}}],"isLastSet":false,"index":0,"isStart":true,"startDuration":1469689001989,"isEnd":true,"endDuration":1469689003323,"speed":"00:00:01"}],"setType":"Set","isSuper":false,"index":0}],"time":"2016-07-28T06:56:52.800Z"}};

console.log(_.isEqual(object, object1));//return true

If all the keys and values for those keys are same in both the objects then it will return true, otherwise return false.

User · Answer

You can serialize simple data to check for equality   data1    firstName   John   lastName   Smith    data2    firstName   Jane   lastName   Smith    JSON stringify data1      JSON stringify data2    This will give you something like    firstName  John  lastName  Smith          firstName  Jane  lastName  Smith      As a function     function compare a  b      return JSON stringify a      JSON stringify b     compare data1  data2     EDIT  If you re using chai like you say  check out http   chaijs com api bdd  equal-section  EDIT 2  If you just want to check keys     function compareKeys a  b      var aKeys   Object keys a  sort      var bKeys   Object keys b  sort      return JSON stringify aKeys      JSON stringify bKeys       should do it

User · Answer

To compare two objects along with all attributes of it  I followed this code and it didn t require tostring   or json compar  x000D   x000D  if user1 equals user2     console log  Both are equal      x000D   x000D   x000D   e

User · Answer

2 Here a short ES6 variadic version   function objectsHaveSameKeys    objects       const allKeys   objects reduce  keys  object    gt  keys concat Object keys object            const union   new Set allKeys      return objects every object   gt  union size     Object keys object  length       A little performance test  MacBook Pro - 2 8 GHz Intel Core i7  Node 5 5 0    var x       var y        for  var i   0  i  lt  5000000    i        x i    i      y i    i      Results   objectsHaveSameKeys x  y     took  4996 milliseconds compareKeys x  y                   took 14880 milliseconds hasSameProps x y                   after 10 minutes I stopped execution

User · Answer

If you want deep validation like  speculees  here s an answer using deep-keys  disclosure  I m sort of a maintainer of this small package      obj1 should have all of obj2 s properties var deepKeys   require  deep-keys    var     require  underscore    assert 0       difference deepKeys obj2   deepKeys obj1   length       obj1 should have exactly obj2 s properties var deepKeys   require  deep-keys    var     require  lodash    assert 0       xor deepKeys obj2   deepKeys obj1   length     or with chai   var expect   require  chai   expect  var deepKeys   require  deep-keys       obj1 should have all of obj2 s properties expect deepKeys obj1   to include members deepKeys obj2       obj1 should have exactly obj2 s properties expect deepKeys obj1   to have members deepKeys obj2

User · Answer

Here is my attempt at validating JSON properties  I used  casey-foster  s approach  but added recursion for deeper validation  The third parameter in function is optional and only used for testing     compare json2 to json1 function isValidJson json1  json2  showInConsole         if   showInConsole          showInConsole   false       var aKeys   Object keys json1  sort        var bKeys   Object keys json2  sort         for  var i   0  i  lt  aKeys length  i               if  showInConsole              console log  ---------    JSON stringify aKeys i            JSON stringify bKeys i             if  JSON stringify aKeys i       JSON stringify bKeys i                   if  typeof json1 aKeys i        object       contains another obj                  if  showInConsole                      console log  Entering     JSON stringify aKeys i                     if   isValidJson json1 aKeys i    json2 bKeys i    showInConsole                        return false     if recursive validation fails                  if  showInConsole                      console log  Leaving     JSON stringify aKeys i                              else                console warn  validation failed at     aKeys i                return false     if attribute names dont mactch                        return true

User · Answer

If you want to check if both objects have the same properties name  you can do this   function hasSameProps  obj1  obj2       return Object keys  obj1   every  function  prop         return obj2 hasOwnProperty  prop             var obj1     prop1   hello   prop2   world   prop3   1 2 3 4 5         obj2     prop1   hello   prop2   world   prop3   1 2 3 4 5      console log hasSameProps obj1  obj2      In this way you are sure to check only iterable and accessible properties of both the objects   EDIT - 2013 04 26   The previous function can be rewritten in the following way   function hasSameProps  obj1  obj2         var obj1Props   Object keys  obj1            obj2Props   Object keys  obj2         if   obj1Props length    obj2Props length             return obj1Props every  function  prop               return obj2Props indexOf  prop    gt   0                         return false      In this way we check that both the objects have the same number of properties  otherwise the objects haven t the same properties  and we must return a logical false  then  if the number matches  we go to check if they have the same properties   Bonus  A possible enhancement could be to introduce also a type checking to enforce the match on every property

[javascript] How can I check that two objects have the same set of property names?

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