forked from Research/WhisperCom
46 lines
1.0 KiB
Markdown
46 lines
1.0 KiB
Markdown
|
# JSON Patch and Diff
|
||
|
|
|
||
|
|
## Patches
|
||
|
|
|
||
|
|
JSON Patch ([RFC 6902](https://tools.ietf.org/html/rfc6902)) defines a JSON document structure for expressing a sequence of operations to apply to a JSON) document. With the `patch` function, a JSON Patch is applied to the current JSON value by executing all operations from the patch.
|
||
|
|
|
||
|
|
??? example
|
||
|
|
|
||
|
|
The following code shows how a JSON patch is applied to a value.
|
||
|
|
|
||
|
|
```cpp
|
||
|
|
--8<-- "examples/patch.cpp"
|
||
|
|
```
|
||
|
|
|
||
|
|
Output:
|
||
|
|
|
||
|
|
```json
|
||
|
|
--8<-- "examples/patch.output"
|
||
|
|
```
|
||
|
|
|
||
|
|
## Diff
|
||
|
|
|
||
|
|
The library can also calculate a JSON patch (i.e., a **diff**) given two JSON values.
|
||
|
|
|
||
|
|
!!! success "Invariant"
|
||
|
|
|
||
|
|
For two JSON values *source* and *target*, the following code yields always true:
|
||
|
|
|
||
|
|
```cüü
|
||
|
|
source.patch(diff(source, target)) == target;
|
||
|
|
```
|
||
|
|
|
||
|
|
??? example
|
||
|
|
|
||
|
|
The following code shows how a JSON patch is created as a diff for two JSON values.
|
||
|
|
|
||
|
|
```cpp
|
||
|
|
--8<-- "examples/diff.cpp"
|
||
|
|
```
|
||
|
|
|
||
|
|
Output:
|
||
|
|
|
||
|
|
```json
|
||
|
|
--8<-- "examples/diff.output"
|
||
|
|
```
|