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### jsoncons::mergepatch::from_diff
```cpp
#include <jsoncons_ext/mergepatch/mergepatch.hpp>
template <typename Json>
Json from_diff(const Json& source, const Json& target)
```
Create a JSON Merge Patch from a diff of two json documents.
#### Return value
Returns a JSON Merge Patch.
### Examples
#### Create a JSON Merge Patch
This example is from [RFC 7386](https://datatracker.ietf.org/doc/html/rfc7386#section-3).
```cpp
#include <jsoncons/json.hpp>
#include <jsoncons_ext/mergepatch/mergepatch.hpp>
using jsoncons::json;
namespace mergepatch = jsoncons::mergepatch;
int main()
{
json source = json::parse(R"(
{
"title": "Goodbye!",
"author" : {
"givenName" : "John",
"familyName" : "Doe"
},
"tags":[ "example", "sample" ],
"content": "This will be unchanged"
}
)");
json target = json::parse(R"(
{
"title": "Hello!",
"author": {
"givenName": "John"
},
"tags": [
"example"
],
"content": "This will be unchanged",
"phoneNumber": "\u002B01-123-456-7890"
}
)");
auto patch = mergepatch::from_diff(source, target);
mergepatch::apply_merge_patch(source, patch);
std::cout << "(1)\n" << pretty_print(patch) << '\n';
std::cout << "(2)\n" << pretty_print(source) << '\n';
}
```
Output:
```
(1)
{
"author": {
"givenName": "John"
},
"content": "This will be unchanged",
"phoneNumber": "+01-123-456-7890",
"tags": ["example"],
"title": "Hello!"
}
(2)
{
"author": {
"familyName": null
},
"phoneNumber": "+01-123-456-7890",
"tags": ["example"],
"title": "Hello!"
}
(3)
{
"author": {
"givenName": "John"
},
"content": "This will be unchanged",
"phoneNumber": "+01-123-456-7890",
"tags": ["example"],
"title": "Hello!"
}
```
|
