Chrome 36 introduced native Object.observe implementation and I think it may be conflicting with yours: http://www.chromestatus.com/features/6147094632988672

I am still researching the issue and will offer more details as I find them.

Anyone got a copy?

I'm compiling all of my JS files into a single file with grunt, and the following line is forcing the browser to attempt to download a file that does not exist:
//# sourceMappingURL=json-patch.min.js.map

Manually specifying this in the file is not required, any browser that supports map files will automatically look for them in the same directory. It's only required if you want to put the map files in a different directory.

I.e.

new_obj = apply(obj, patch)

remove(new_obj, path) // == obj

Shouldn't take more than a minute

> jsonpatch.compare({a: {}}, {a: [1]});
[{op: "add", path: "/a/0", value: 1}]

Shouldn't be the empty object replaced with the array? the value is no longer an object.

[{op: "replace", path: "/a", value: [1]}]

RFC 6902, section 4.1 ("add") says: "The operation object MUST contain a "value" member whose content specifies the value to be added."

jsonpatch.compare() can, however, produce an add operation with no value when the value is undefined.

Test case:

original = {foo: 1};
changed = {foo: 1, bar: undefined};
patch = jsonpatch.compare(original, changed);
jsonpatch.apply(original, patch);

Result: Error: 'value' MUST be defined

Hi,

Isn't a different concern for this project to have its own Object.observer? Wouldn't be better if it uses a external module to do it or spin off the current one?

https://github.com/jdarling/Object.observe

Even further, is is really necessary to observe a object to create a diff? Wouldn't be the responsibility of the ones using this module to know when and where to make a diff? So, is the concern of json-path to do that?

ps: json-patch is a great project! tks!

Hello,

You can try the following code:

var jsonpatch = require('./src/json-patch');
var patches = [{op: 'add', value: [], path: '/foo'}, {op: 'add', value: 2, path: '/foo/-'}];
jsonpatch.validate(patches, {});
console.log(patches);

It outputs:

[ { op: 'add', value: [ 2 ], path: '/foo' },
  { op: 'add', value: 2, path: '/foo/-' } ]

As you can see the value object of the first patch has been modified. Instead of an empty array it is now an array containing the value of the second patch.

assume that there's an object like:

var obj_src = {
  name: "jone",
  city: "Sydney",
  pets: [
    {nickname: "volo", category: "dog", age: "3"},
    {nickname: "wabit", category: "cat", age: "5"},
    {nickname: "moaoaa", category: "tiger", age: "1"},
    {nickname: "gofast", category: "lion", age: "3"}
  ]
}

if pets' nickname is unique, can I use patch like {op: "replace", path: "/pets[nickname=wabit]/age", value: "9"} to alter wabit's age instead using {op: "replace", path: "/pets/1/age", value: "9"} because sometimes I don't know the array order.

In this test patch has no the 'contactDetails' field:

var collection1 = {},
    collection2 = {},
    iteration = 100;

var json1 = { firstName:"Joachim", lastName:"Wester", num:123, contactDetails: { phoneNumbers: [ { number:"555-123" }] } },
    json2 = { firstName:"Ivan", lastName:"test", key: [], contactDetails: { phoneNumbers: [ { number:"555-123" }, { number:"666-123" }] } };

//fill array
var t0 = performance.now();
for(var i=0; i < iteration; i++) {
    collection1['key'+i] = _.clone(json1); //underscore.js
    collection2['key'+i] = _.clone(json2); //underscore.js
}
var t1 = performance.now();
console.log('Test 0. Took ' + (t1 - t0) + ' ms');
console.log(collection1);
console.log(collection2);

//get patch
var t0 = performance.now();
for(var i in collection1) {
    var patch = jsonpatch.compare(collection1[i], collection2[i]);
}
var t1 = performance.now();
console.log('Test 1. Took ' + (t1 - t0) + ' ms');
console.log(patch);

//// output
[Object, Object, Object, Object]
0: Object
op: "remove"
path: "/num"
proto: Object
1: Object
op: "replace"
path: "/lastName"
value: "test"
proto: Object
2: Object
op: "replace"
path: "/firstName"
value: "Ivan"
proto: Object
3: Object
op: "add"
path: "/key"
value: Array[0]
proto: Object
length: 4
proto: Array[0]

#35 was merged w.o. tests

Here's the test that fails:

it('should generate nice remove op on array.splice', function() {
          obj = { items: ["a", "b", "c"]};
          var observer = jsonpatch.observe(obj);

          obj.items.splice(1, 1); // <<-- removing second item in-place

          patches = jsonpatch.generate(observer);

          // Expect to have only one 'remove' operation, otherwise patches for big arrays are way too long:
          // essentially it says to replace *every* item and remove last one.
          // In case array items are not trivial, this may cause performance issues too, I guess.
          expect(patches).toEqual([
              { op: 'remove', path: '/items/1' }
          ]);

          obj2 = { items: ["a", "b", "c"]};
          jsonpatch.apply(obj2,patches);
          expect(obj).toEqualInJson(obj2);
      });

Now it fails as following:

duplex generate should generate nice remove on array.splice.
Expected [ { op : 'remove', path : '/items/2' }, { op : 'replace', path : '/items/1', value : 'c' } ] to equal [ { op : 'remove', path : '/items/1' } ].

tks

I am looking for a way, without introducing a new library, to read value at given path using json-pointer notation. Something like jsonpatch.get(object, "/pointer/to/key") to return value at that path.

I know it's really neither patching's responsibility, nor it's specified anywhere in RFC but if we have such mechanism(method), it can be very useful.

Hi,

if I call jsonpatch.generate() the first time it generates the patches normally, but modifies the observed object, so the subsequent calls to jsonpatch.generate() don't generate any patches. Is it intentional, or is it a bug?

Regards
Gábor

Consider the following code:

var object = {
  test: undefined
};

var observer = jsonpatch.observe(object);
var result = jsonpatch.generate(observer);

JSON-Patch throws a SyntaxError exception when trying to generate the patch at line 421 of json-patch-duplex.js (in the function _generate):

mirror[key] = JSON.parse(JSON.stringify(obj[key]));

obj[key] is undefined, causing JSON.stringify() to return undefined, which JSON.parse() cannot handle ("Unexpected token u").

The expected behavior is that no patches should be generated, as nothing has changed.

The following code does not work correctly:

var obj = {"hello": "world"};
jsonpatch.apply(obj, [{"op":"replace","path":"/","value":{"hello": "universe"}}]);

Expected result obj:

{"hello": "universe"}

Actual result obj:

{"hello": "world", "": {"hello": "universe"}}

Spec:
http://tools.ietf.org/html/rfc6902#section-4.6

Implementation:

    test: function (obj, key) {
      return(JSON.stringify(obj[key]) === JSON.stringify(this.value));
    },

It doesn't work if 2 arrays/objects are equals (from the RFC definition) but ordered differently.

JSON.stringify(['foo', 'bar']) === JSON.stringify(['bar', 'foo']); //false

I totally understand that jsonpatch.generate modifies the objects it watches to always only detect most recent changes (as discussed in #18 ) of an object. In my opinion this should not be the case for jsonpatch.compare as I explicitly use this method with objects that are not under control of jsonpatch observers. Thus modification of these objects should be under my control as well.

Thanks for this project.

A nice feature would be to validate that a patch document is a valid patch doc. This would allow users to pre-validate that the client sent a valid patch document before the server uses it.

Something like:
jsonpatch.isValid(patch); //true = valid, false = invalid

Or you could return errors, but that might be difficult. Ultimately, if a client sends a bad patch, we're just going to return an http bad request.

My application need to get a diff between two different objects, obj1 and obj2 !
Is there a syntax to use it like that?
I don't have an "original object" that is modified at run-time, in order to "observe" it!
I load obj1 from a database and build obj2 from a form, and need to have the diff!
Thanks,
Teo

I don't know does it issue related to fast-json-path directly but hope you could give some advices. Let's say we have the following document for patching:

{ "foo": [ "bar", "baz", "foo", "fox" ] }

And trying to remove "bar" and "baz" elements in single operations batch:

[
    { "op": "remove", "path": "/foo/0" },
    { "op": "remove", "path": "/foo/1" }
]

I'm expecting to get the following result:

    { "foo": ["foo", "fox" ] }

But rather then I get the following:

 { "foo": [ "baz", "fox" ] }

I understand that after applying first operation { "op": "remove", "path": "/foo/0" } array indexes are get recalculates and the following operation { "op": "remove", "path": "/foo/1" } applies to updated array.

Let me give some advises how could I workaround this?

when null replaces an object.

jsonpatch.compare({a: {}}, {a: null});

In response from the server, To and From address come as null:

"To":{"Address$":null}

Even if I update it with a new value (patch request), server still restores the null value.

In your readme you compare to a two out of the three other json-patch libraries mentioned on jsonpatch.com. Any chance you could add the third one to the comparison?

A TypeError exception is being thrown when the path parameter isn't specified (or misspelled) in a patch. This is handled correctly when the op and value parameters aren't specified, but not path.

TypeError: Cannot read property 'split' of undefined
at Object.apply (node_modules/fast-json-patch/src/json-patch-duplex.js:548:34)
at Object.validate (node_modules/fast-json-patch/src/json-patch-duplex.js:686:23)

For example:

[
  {
    "op"    : "replace",
    "value" : "Not working"
  }
]

@Starcounter-Jack I'm on 0.5.1.

My object: {foo: null}
My patch: [ { op: 'replace', path: '/foo', value: 'whatever' } ]
Returns: "Cannot perform the operation at a path that does not exist".
Expected: {foo: 'whatever'}

var x = {};

jsonpatch.observe(x, function() {
  console.log('One');
});
jsonpatch.observe(x, function() {
  console.log('Two');
});

x.someValue = true;

It should execute both functions.

Originally described here

When you do a comparison on an object that includes dates, all dates end up resulting in patches. This is because JSON.parse(JSON.stringify)) is used to generate an internal cache object, but that does not result in an object with identical values. Dates get converted to strings:

d = new Date();
foo = {x: 10, y: "test", z: d};
jsonpatch.observe(foo);
bar = jsonpatch.observe(foo);
jsonpatch.generate(bar);

var obj = {firstName: "Albert"};
var patches = [{op: "add", path: "/lastName", value:"Wester"}];
jsonpatch.apply(obj,patches);
obj = {firstName: 'Albert' },lastName:'Wester' }
If path = "lastName"
The result
{ '0': 'W', '1': 'e', '2': 's', '3': 't', '4': 'e', '5': 'r' }

why?

When observing multiple obects with the same structure the callback is triggerd on non changed objects.

How to reproduce

<!DOCTYPE html>
<head>
  <title>JSON-Patch : Tester</title>
  <script src="lib/angular.js"></script>
  <script src="lib/json-patch-duplex.js"></script>
</head>

<body ng-app ng-controller="controller">
  <input ng-model="model1.FirstName"/>
  <input ng-model="model1.LastName"/>
  <br>
  <input ng-model="model2.FirstName"/>
  <input ng-model="model2.LastName"/>
</body>

<script>

  function controller($scope) {

      $scope.model1 = { FirstName:"Model A", LastName:"Model A"};
      $scope.model2 = { FirstName:"Model B", LastName:"Model B"};

     // Observe the model
      jsonpatch.observe($scope.model1, function (patches) {
          console.log("model1:observe callback:" + JSON.stringify(patches));
      });

      jsonpatch.observe($scope.model2, function (patches) {
          console.log("model2:observe callback:" + JSON.stringify(patches));
      });

  }

</script>

Maybe now is a good time to consider this a 1.0 release

TypeError: Cannot call method 'indexOf' of undefined
    at Object.apply (/Users/sonny/Projects/JSON-Patch/src/json-patch.js:129:29

But I'm not sure it makes sense to support the root path.
It seems RFC 6902 lacks a word or too about it 👅 .

• add and replace ops would replace the complete document
• test would test for equality as for any other value
• what about of move, copy and delete?

Example

var object = {someValues : ["one", "two"]};
var object2 = {someValues : ["one", "two", "new value"]};
var result = jsonpatch.compare(object, object2 );
result is [{"op":"add", "path": "/someValues/2", "value": "new value"}];

If you add an element to an array at the end of it - it should end with "path/-" and not the index of the new element

I think this is related to #65, that I openeed a while ago. But in this case the result is worse as patch is completely wrong. Here's the test case:

it('should generate valid patch on remove array item after changing its property', function() {
      obj = {arr: [{ lastName:"Einstein" }, {lastName:"123"}]};
      var observer = jsonpatch.observe(obj);

      // 2 changes!
      obj.arr[0].lastName = 'Some';
      obj.arr.splice(0, 1);

      patches = jsonpatch.generate(observer);
      expect(patches).toEqual([
        { op: 'remove', path: '/arr/0' }
      ]);
    });

Fails as: Expected [ ] to equal [ { op : 'remove', path : '/arr/0' } ].

Code

var a = {as: '234', b: 3};
var observer = jsonpatch.observe(a);
a.b = 4
a.as = 3
a.y = 7
var patches = jsonpatch.generate(observer);

Returns only last change:

[{ op: "add", path: "/y", value: 7 }]

I am using the test operation for some optimistic concurrency, and I noticed that the result from the apply method only takes into consideration the last operation.

From RFC-6902

   If a normative requirement is violated by a JSON Patch document, or
   if an operation is not successful, evaluation of the JSON Patch
   document SHOULD terminate and application of the entire patch
   document SHALL NOT be deemed successful.

   See [RFC5789], Section 2.2 for considerations regarding handling
   errors when JSON Patch is used with the HTTP PATCH method, including
   suggested status codes to use to indicate various conditions.

   Note that the HTTP PATCH method is atomic, as per [RFC5789].
   Therefore, the following patch would result in no changes being made
   to the document at all (because the "test" operation results in an
   error):

   [
     { "op": "replace", "path": "/a/b/c", "value": 42 },
     { "op": "test", "path": "/a/b/c", "value": "C" }
   ]

Therefore the apply should at the very least return false if any operation fails.
Currently the result variable is only ever set and returned.

If we remove items from an array using Array.prototype.splice() the order of patches generated by jsonpatch.generate() differs, depending on whether jsonpatch.observe() uses native Object.observe or a shim.

Lets take a sample test case:

it('should generate the same patch using Object.observe and shim after removing items from array', 
function() {
      var arr1 = [
        ["Albert", "Einstein"],
        ["Erwin", "Shrodinger"]
      ];

      var arr2 = arr1.slice();

      var observer1 = jsonpatch.observe(arr1);
      arr1.splice(0, 2);

      var objectObservePatches = jsonpatch.generate(observer1);

      var _observe = Object.observe;
      Object.observe = undefined;

      var observer2 = jsonpatch.observe(arr2);
      arr2.splice(0, 2);

      var shimPatches = jsonpatch.generate(observer2);

      expect(objectObservePatches).toEqual(shimPatches); //fails

      Object.observe = _observe;
});

the value stored in objectObservePatches is

[ { op : 'remove', path : '/1' }, { op : 'remove', path : '/0' }, 
{ op : 'replace', path : '/length', value : 0 } ]

whereas shimPatches contains array:

[ { op : 'remove', path : '/0' }, { op : 'remove', path : '/1' } ]

Ignoring patches related to length property (#14) patches generated by Object.observe() version indicate that we first removed item with index 1 and then 0 whereas shim version suggests something opposite.

(Continued from Palindrom/Palindrom#21)

PuppetJs in debug mode (currently ON by default) validates outgoing patches:

   if(this.debug) {
      this.validateSequence(this.remoteObj, patches);
    }

in which case the error should be reported. I am glad that we both agree :)

@miyconst: Current validation is implemented here: https://github.com/Starcounter-Jack/JSON-Patch/blob/master/src/json-patch-duplex.js#L632

And it is throwing OPERATION_VALUE_REQUIRED for undefined values, which should be replaced with VALUE_OBJECT_CANNOT_CONTAIN_UNDEFINED.

It should not be mixed. The current check for undefined value (OPERATION_VALUE_REQUIRED) should be kept. A new check for undefined property of the value (if the value is an object) should be added after it (VALUE_OBJECT_CANNOT_CONTAIN_UNDEFINED).

@miyconst could you prepare a solution for this on a separate branch in https://github.com/Starcounter-Jack/JSON-Patch? Publish code on a separate branch for review. The changes should include test and update to README.md

I think that the 0.5 versioning is a bit to conservative. Should we go for 1.0 with the current bits?

In native Object.observe version (Chrome 28 & 30), array length is reported as part of the change records.

I don't think this is an error in Chrome, but I think JSON-Patch should filter out length from it's own generated patch

See http://jsfiddle.net/U4mZJ/3/

For a sample array, generated patch is:

[
 {"op":"replace","path":"/0","value":99},
 {"op":"add","path":"/2","value":3},
 {"op":"replace","path":"/length","value":3}
]

I will fix this soon

I've noticed a quite important inconsistency in the way JSON-Patch handles registering the same callback multiple times, on the same observed object.

It turns out, that registering the same callback multiple times, on the same object using jsonpatch.observe, which takes advantage of native Object.observe function, causes callback to be invoked the same number of times, if any changes occur in the observed object, whereas jsonpatch.observe using Object.observe shim invokes the callback only once, no matter how many times the jsonpatch.observe function was called.

Worth mentioning is a fact, that native Object.observe acts as jsonpatch.observe with shim.

I've prepared a set of test cases: http://jsfiddle.net/Qyb4w/

Support for NPM (#8) is a great addition but it breaks client side usage. test-duplex.html fails at all tests with error Uncaught ReferenceError: exports is not defined

Sorry for the question here but I'm very interested in how do you guys patch your JSON document in your projects in production?

How do you store your documents (Redis, pure json files, MongoDB or something else)? Please share your experience or point me right direction.

Let me explain my question. I've found livedb project https://github.com/share/livedb that make possible to issue partial updating of big JSON tree with OP supporting.

At now livedb support several ottypes https://github.com/ottypes among which json0 https://github.com/ottypes/json0

Do you plan to contribute this project to allow possibility make OT operations with json-patch?

Excerpt from JSON-patch spec (section 4.1):

An element to add to an existing array - whereupon the supplied
      value is added to the array at the indicated location.  Any
      elements at or above the specified index are shifted one position
      to the right.  The specified index MUST NOT be greater than the
      number of elements in the array.  If the "-" character is used to
      index the end of the array (see [RFC6901]), this has the effect of
      appending the value to the array.

var obj = { arr: [ "item 1", "item 2" ] }
var patch = [ { op: 'add', path: '/arr/-', value: 'item 3' } ]

// obj should be { arr: [ "item 1", "item 2", "item 3" ] }
// but is { arr: [ "item 3", "item 1", "item 2" ] }

I think it's reasonable to not generate hyphen patches, but it should be possible to apply them.

I think change to https://github.com/Starcounter-Jack/JSON-Patch/blob/master/src/json-patch.js#L91 would work as follows:

var index = keys[t] === '-' ? obj.length : parseInt(keys[t], 10);

I can create formal pull request with updated tests if you would prefer. What's your build process?