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api/json_editable_view/index.md

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+# nlohmann::json_editable_view
+
+Defined in header `<nlohmann/json_view.hpp>`
+
+```
+using json_editable_view = basic_json_view<json, true>;
+```
+
+This type is a [`basic_json_view`](https://json.nlohmann.me/api/basic_json_view/index.md) of a value of a [`json_editable_document`](https://json.nlohmann.me/api/json_editable_document/index.md). It offers the same read-only interface as [`json_view`](https://json.nlohmann.me/api/json_view/index.md); what is different is what it can be a view *of* -- a value that [`set`](https://json.nlohmann.me/api/basic_json_document/set/index.md) and [`push_back`](https://json.nlohmann.me/api/basic_json_document/push_back/index.md) can change, with every view still referring to it seeing the change, see [Edits](https://json.nlohmann.me/api/basic_json_document/#edits).
+
+## Examples
+
+Example
+
+The example below is the same as [`json_editable_document`'s](https://json.nlohmann.me/api/json_editable_document/index.md): every view read back out of the document -- `doc.root()` and the views nested under it -- sees the edits made through `set`.
+
+```
+#include <iostream>
+#include <nlohmann/json_view.hpp>
+
+using json = nlohmann::json;
+using json_editable_document = nlohmann::json_editable_document;
+using json_editable_view = nlohmann::json_editable_view;
+
+int main()
+{
+    // a configuration file, as it might be read from disk
+    const std::string text = R"({"name": "cache", "host": "db1", "port": 6379, "price": 19.90})";
+    std::cout << text << "\n\n";
+
+    // patch two fields -- "price" is never touched
+    json_editable_document doc = json_editable_document::parse(text);
+    doc.set(doc.root(), "host", "db2");
+    doc.set(doc.root(), "retries", 3);
+
+    // member order (the new member at the end) and the untouched number's
+    // exact spelling survive
+    std::cout << doc.root().dump(-1, ' ', false, json_editable_view::number_format::source) << '\n';
+
+    // the same patch on a plain json value: keys are sorted (object_t is a
+    // std::map), and "price" is rewritten even though the patch never
+    // touched it
+    json plain = json::parse(text);
+    plain["host"] = "db2";
+    plain["retries"] = 3;
+    std::cout << plain.dump() << '\n';
+}
+```
+
+Output:
+
+```
+{"name": "cache", "host": "db1", "port": 6379, "price": 19.90}
+
+{"name":"cache","host":"db2","port":6379,"price":19.90,"retries":3}
+{"host":"db2","name":"cache","port":6379,"price":19.9,"retries":3}
+```
+
+## See also
+
+- [json_editable_document](https://json.nlohmann.me/api/json_editable_document/index.md) - the document type this view refers into
+- [json_view](https://json.nlohmann.me/api/json_view/index.md) - the corresponding read-only view
+- [ordered_json_editable_view](https://json.nlohmann.me/api/ordered_json_editable_view/index.md) - the corresponding view for `ordered_json_editable_document`
+
+## Version history
+
+Since version 3.13.0 unreleased.