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### jsoncons::jsonpointer::add
Adds a value to an object or inserts it into an array at the target location.
If a value already exists at the target location, that value is replaced.
```cpp
#include <jsoncons_ext/jsonpointer/jsonpointer.hpp>
template <typename Json,typename T>
void add(Json& target,
const basic_json_pointer<Json::char_type>& location,
T&& value,
bool create_if_missing = false); (1) (since 0.167.0)
template <typename Json,typename T>
void add(Json& target,
const basic_json_pointer<Json::char_type>& location,
T&& value,
std::error_code& ec); (2) (since 0.167.0)
template <typename Json,typename T>
void add(Json& target,
const basic_json_pointer<Json::char_type>& location,
T&& value,
bool create_if_missing,
std::error_code& ec); (3) (since 0.167.0)
template <typename Json,typename StringSource,typename T>
void add(Json& target,
const StringSource& location_str,
T&& value,
bool create_if_missing = false); (4)
template <typename Json,typename StringSource,typename T>
void add(Json& target,
const StringSource& location_str,
T&& value,
std::error_code& ec); (5)
template <typename Json,typename StringSource,typename T>
void add(Json& target,
const StringSource& location_str,
T&& value,
bool create_if_missing,
std::error_code& ec); (6) (since 0.162.0)
```
Inserts a value into the target at the specified location, or if the location specifies an object member that already has the same key, assigns the new value to that member
- If `location` specifies an array index, a new value is inserted into the array at the specified index.
- If `location` specifies an object member that does not already exist, a new member is added to the object.
- If `location` specifies an object member that does exist, that member's value is replaced.
#### Parameters
<table>
<tr>
<td>target</td>
<td>JSON value</td>
</tr>
<tr>
<td>location</td>
<td>A <a href="basic_json_pointer.md">basic_json_pointer</a></td>
</tr>
<tr>
<td>location_str</td>
<td>A JSON Pointer provided as a string, string view, or C-string</td>
</tr>
<tr>
<td>value</td>
<td>New or replacement value</td>
</tr>
<tr>
<td><code>create_if_missing</code> (since 0.162.0)</td>
<td>Create key-object pairs when object key is missing</td>
</tr>
<tr>
<td><code>ec</code></td>
<td>out-parameter for reporting errors in the non-throwing overload</td>
</tr>
</table>
#### Return value
None
### Exceptions
(1) Throws a [jsonpointer_error](jsonpointer_error.md) if `add` fails.
(2)-(3) Sets the out-parameter `ec` to the [jsonpointer_error_category](jsonpointer_errc.md) if `add` fails.
### Examples
#### Insert or assign an object member at a location_str that already exists
```cpp
#include <jsoncons/json.hpp>
#include <jsoncons_ext/jsonpointer/jsonpointer.hpp>
using jsoncons::json;
namespace jsonpointer = jsoncons::jsonpointer;
int main()
{
auto target = json::parse(R"(
{ "foo": "bar", "baz" : "abc"}
)");
std::error_code ec;
jsonpointer::add(target, "/baz", json("qux"), ec);
if (ec)
{
std::cout << ec.message() << '\n';
}
else
{
std::cout << target << '\n';
}
}
```
Output:
```json
{"baz":"qux","foo":"bar"}
```
#### Add a value to a location_str after creating objects when missing object keys
```cpp
#include <iostream>
#include <jsoncons/json.hpp>
#include <jsoncons_ext/jsonpointer/jsonpointer.hpp>
using jsoncons::json;
namespace jsonpointer = jsoncons::jsonpointer;
int main()
{
std::vector<std::string> keys = {"foo","bar","baz"};
jsonpointer::json_pointer location_str;
for (const auto& key : keys)
{
location_str /= key;
}
json doc;
jsonpointer::add(doc, location_str, "str", true);
std::cout << pretty_print(doc) << "\n\n";
}
```
Output:
```json
{
"foo": {
"bar": {
"baz": "str"
}
}
}
```
|
