# basic_json

!!! note
    
    This page is under construction.

Defined in header `<json.hpp>`

```cpp
template<
    template<typename U, typename V, typename... Args> class ObjectType = std::map,
    template<typename U, typename... Args> class ArrayType = std::vector,
    class StringType = std::string,
    class BooleanType = bool,
    class NumberIntegerType = std::int64_t,
    class NumberUnsignedType = std::uint64_t,
    class NumberFloatType = double,
    template<typename U> class AllocatorType = std::allocator,
    template<typename T, typename SFINAE = void> class JSONSerializer = adl_serializer,
    class BinaryType = std::vector<std::uint8_t>
>
class basic_json;
```

## Specializations

- [**json**](../json.md) - default specialization
- [**ordered_json**](../ordered_json.md) - specialization that maintains the insertion order of object keys

## Template parameters

| Template parameter   | Description | Derived type |
| -------------------- | ----------- | ------------ |
| `ObjectType`         | type for JSON objects | [`object_t`](object_t.md) |
| `ArrayType`          | type for JSON arrays | [`array_t`](array_t.md) |
| `StringType`         | type for JSON strings and object keys | `string_t` |
| `BooleanType`        | type for JSON booleans | `boolean_t` |
| `NumberIntegerType`  | type for JSON integer numbers | [`number_integer_t`](number_integer_t.md) |
| `NumberUnsignedType` | type for JSON unsigned integer numbers | [`number_unsigned_t`](number_unsigned_t.md) |
| `NumberFloatType`    | type for JSON floating-point numbers | [`number_float_t`](number_float_t.md) |
| `AllocatorType`      | type of the allocator to use | |
| `JSONSerializer`     | the serializer to resolve internal calls to `to_json()` and `from_json()` | |
| `BinaryType`         | type for binary arrays | `binary_t` |

## Iterator invalidation

Todo

## Member types

- [**value_t**](value_t.md) - the JSON type enumeration
- [**json_pointer**](../json_pointer.md) - JSON Pointer implementation
- json_serializer
- [**error_handler_t**](error_handler_t.md) - type to choose behavior on decoding errors
- [**cbor_tag_handler_t**](cbor_tag_handler_t.md) - type to choose how to handle CBOR tags
- initializer_list_t
- [**input_format_t**](input_format_t.md) - type to choose the format to parse
- json_sax_t

### Exceptions

- [**exception**](exception.md) - general exception of the `basic_json` class
    - [**parse_error**](parse_error.md) - exception indicating a parse error
    - [**invalid_iterator**](invalid_iterator.md) - exception indicating errors with iterators
    - [**type_error**](type_error.md) - exception indicating executing a member function with a wrong type
    - [**out_of_range**](out_of_range.md) - exception indicating access out of the defined range
    - [**other_error**](other_error.md) - exception indicating other library errors

### Container types

| Type                   | Definition |
| ---------------------- | ---------- |
| value_type             | `#!cpp basic_json` |
| reference              | `#!cpp value_type&` |
| const_reference        | `#!cpp const value_type&` |
| difference_type        | `#!cpp std::ptrdiff_t` |
| size_type              | `#!cpp std::size_t` |
| allocator_type         | `#!cpp AllocatorType<basic_json>` |
| pointer                | `#!cpp std::allocator_traits<allocator_type>::pointer` |
| const_pointer          | `#!cpp std::allocator_traits<allocator_type>::const_pointer` |
| iterator               | [LegacyBidirectionalIterator](https://en.cppreference.com/w/cpp/named_req/BidirectionalIterator) |
| const_iterator         | constant [LegacyBidirectionalIterator](https://en.cppreference.com/w/cpp/named_req/BidirectionalIterator) |
| reverse_iterator       |  |
| const_reverse_iterator |  |
| iteration_proxy        |  |

### JSON value data types

- object_comparator_t
- [**object_t**](object_t.md) - type for objects
- [**array_t**](array_t.md) - type for arrays
- [**string_t**](string_t.md) - type for strings
- [**boolean_t**](boolean_t.md) - type for booleans
- [**number_integer_t**](number_integer_t.md) - type for numbers (integer)
- [**number_unsigned_t**](number_unsigned_t.md) - type for numbers (unsigned)
- [**number_float_t**](number_float_t.md) - type for numbers (floating-point)
- binary_t

### Parser callback

- [**parse_event_t**](parse_event_t.md) - parser event types
- [**parser_callback_t**](parser_callback_t.md) - per-element parser callback type

## Member functions

- [(constructor)](basic_json.md)
- [(destructor)](~basic_json.md)
- [**operator=**](operator=.md) - copy assignment
- [**array**](array_t.md) (static) - explicitly create an array
- [**binary**](binary.md) (static) - explicitly create a binary array
- [**object**](object_t.md) (static) - explicitly create an object

### Object inspection

Functions to inspect the type of a JSON value.

- [**type**](type.md) - return the type of the JSON value
- [**operator value_t**](operator_value_t.md) - return the type of the JSON value
- [**type_name**](type_name.md) - return the type as string
- [**is_primitive**](is_primitive.md) - return whether type is primitive
- [**is_structured**](is_structured.md) - return whether type is structured
- [**is_null**](is_null.md) - return whether value is null
- [**is_boolean**](is_boolean.md) - return whether value is a boolean
- [**is_number**](is_number.md) - return whether value is a number
- [**is_number_integer**](is_number_integer.md) - return whether value is an integer number
- [**is_number_unsigned**](is_number_unsigned.md) - return whether value is an unsigned integer number
- [**is_number_float**](is_number_float.md) - return whether value is a floating-point number
- [**is_object**](is_object.md) - return whether value is an object
- [**is_array**](is_array.md) - return whether value is an array
- [**is_string**](is_string.md) - return whether value is a string
- [**is_binary**](is_binary.md) - return whether value is a binary array
- [**is_discarded**](is_discarded.md) - return whether value is discarded

### Value access

Direct access to the stored value of a JSON value.

- [**get**](get.md) - get a value
- get_to - get a value
- get_ptr - get a pointer value
- get_ref - get a reference value
- operator ValueType - get a value
- get_binary - get a binary value

### Element access

Access to the JSON value

- [**at**](at.md) - access specified element with bounds checking
- [**operator[]**](operator[].md) - access specified element
- [**value**](value.md) - access specified object element with default value
- [**front**](front.md) - access the first element
- [**back**](back.md) - access the last element

### Lookup

- [**find**](find.md) - find an element in a JSON object
- [**count**](count.md) - returns the number of occurrences of a key in a JSON object
- [**contains**](contains.md) - check the existence of an element in a JSON object

### Iterators

- [**begin**](begin.md) - returns an iterator to the first element
- [**cbegin**](cbegin.md) - returns a const iterator to the first element
- [**end**](end.md) - returns an iterator to one past the last element
- [**cend**](cend.md) - returns a const iterator to one past the last element
- [**rbegin**](rbegin.md) - returns an iterator to the reverse-beginning
- [**rend**](rend.md) - returns an iterator to the reverse-end
- [**crbegin**](crbegin.md) - returns a const iterator to the reverse-beginning
- [**crend**](crend.md) - returns a const iterator to the reverse-end
- [**items**](items.md) - wrapper to access iterator member functions in range-based for

### Capacity

- [**empty**](empty.md) - checks whether the container is empty
- [**size**](size.md) - returns the number of elements
- [**max_size**](max_size.md) - returns the maximum possible number of elements

### Modifiers

- [**clear**](clear.md) - clears the contents
- [**push_back**](push_back.md) - add a value to an array/object
- [**operator+=**](operator+=.md) - add a value to an array/object
- [**emplace_back**](emplace_back.md) - add a value to an array
- [**emplace**](emplace.md) - add a value to an object if key does not exist
- [**erase**](erase.md) - remove elements
- [**insert**](insert.md) - inserts elements
- [**update**](update.md) - updates a JSON object from another object, overwriting existing keys 
- swap - exchanges the values

### Lexicographical comparison operators

- [**operator==**](operator==.md) - comparison: equal
- [**operator!=**](operator!=.md) - comparison: not equal
- operator< - comparison: less than
- operator<= - comparison: less than or equal
- operator> - comparison: greater than
- operator>= - comparison: greater than or equal

### Serialization

- [**dump**](dump.md) - serialization
- to_string - user-defined to_string function for JSON values

### Deserialization

- [**parse**](parse.md) (static) - deserialize from a compatible input
- [**accept**](accept.md) (static) - check if the input is valid JSON
- [**sax_parse**](sax_parse.md) (static) - generate SAX events

### JSON Pointer functions

- [**flatten**](flatten.md) - return flattened JSON value
- [**unflatten**](unflatten.md) - unflatten a previously flattened JSON value

### JSON Patch functions

- [**patch**](patch.md) - applies a JSON patch
- [**diff**](diff.md) (static) - creates a diff as a JSON patch

### JSON Merge Patch functions

- [**merge_patch**](merge_patch.md) - applies a JSON Merge Patch

## Static functions

- [**meta**](meta.md) - returns version information on the library
- [**get_allocator**](get_allocator.md) - returns the allocator associated with the container

### Binary formats

- [**from_bson**](from_bson.md) (static) - create a JSON value from an input in BSON format
- [**from_cbor**](from_cbor.md) (static) - create a JSON value from an input in CBOR format
- [**from_msgpack**](from_msgpack.md) (static) - create a JSON value from an input in MessagePack format
- [**from_ubjson**](from_ubjson.md) (static) - create a JSON value from an input in UBJSON format
- [**to_bson**](to_bson.md) (static) - create a BSON serialization of a given JSON value
- [**to_cbor**](to_cbor.md) (static) - create a CBOR serialization of a given JSON value
- [**to_msgpack**](to_msgpack.md) (static) - create a MessagePack serialization of a given JSON value
- [**to_ubjson**](to_ubjson.md) (static) - create a UBJSON serialization of a given JSON value

## Non-member functions

- operator<<(std::ostream&) - serialize to stream
- operator>>(std::istream&) - deserialize from stream

## Literals

- [**operator""_json**](operator_literal_json.md) - user-defined string literal for JSON values
- [**operator""_json_pointer**](operator_literal_json_pointer.md) - user-defined string literal for JSON pointers

## Helper classes

- std::hash<nlohmann::json\>
- std::less<nlohmann::value_t\>
- std::swap<nlohmann::json\>
