json/doc/mkdocs/docs/api/basic_json/index.md

basic_json

!!! note

This page is under construction.

Defined in header <json.hpp>

template<template<typename, typename, typename...> class ObjectType,  
         template<typename, typename...> class ArrayType,             
         class StringType, class BooleanType, class NumberIntegerType,
         class NumberUnsignedType, class NumberFloatType,             
         template<typename> class AllocatorType,                      
         template<typename, typename = void> class JSONSerializer,    
         class BinaryType>
class basic_json

Specializations

• json
• ordered_json

Template parameters

• ObjectType
• ArrayType
• StringType
• BooleanType
• NumberIntegerType
• NumberUnsignedType
• NumberFloatType
• AllocatorType
• JSONSerializer
• BinaryType

Iterator invalidation

Member types

• value_t
• json_pointer
• json_serializer
• error_handler_t
• cbor_tag_handler_t
• initializer_list_t
• input_format_t
• json_sax_t

Exceptions

• exception
• parse_error
• invalid_iterator
• type_error
• out_of_range
• other_error

Container types

• value_type
• reference
• const_reference
• difference_type
• size_type
• allocator_type
• pointer
• const_pointer
• iterator
• const_iterator
• reverse_iterator
• const_reverse_iterator

JSON value data types

• object_comparator_t
• object_t
• array_t
• string_t
• boolean_t
• number_integer_t
• number_unsigned_t
• number_float_t
• binary_t

Parser callback

• parse_event_t
• parser_callback_t

Member functions

• (constructor)
• (destructor)
• binary (static) - explicitly create a binary array
• array (static) - explicitly create an array
• object (static) - explicitly create an object
• operator= - copy assignment

Object inspection

Functions to inspect the type of a JSON value.

• type - return the type of the JSON value
• is_primitive - return whether type is primitive
• is_structured - return whether type is structured
• is_null - return whether value is null
• is_boolean - return whether value is a boolean
• is_number - return whether value is a number
• is_number_integer - return whether value is an integer number
• is_number_unsigned - return whether value is an unsigned integer number
• is_number_float - return whether value is a floating-point number
• is_object - return whether value is an object
• is_array - return whether value is an array
• is_string - return whether value is a string
• is_binary - return whether value is a binary array
• is_discarded - return whether value is discarded
• operator value_t - return the type of the JSON value

Value access

Direct access to the stored value of a JSON value.

• get - 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 - access specified array element with bounds checking
• at - access specified object element with bounds checking
• operator[] - access specified array element
• operator[] - access specified object element
• value - access specified object element with default value
• front - access the first element
• back - access the last element
• erase - remove elements

Lookup

• find - find an element in a JSON object
• count - returns the number of occurrences of a key in a JSON object
• contains - check the existence of an element in a JSON object

Iterators

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

Capacity

• empty - checks whether the container is empty
• size - returns the number of elements
• max_size - returns the maximum possible number of elements

Modifiers

• clear - clears the contents
• push_back - add an object to an array
• operator+= - add an object to an array
• push_back - add an object to an object
• operator+= - add an object to an object
• emplace_back - add an object to an array
• emplace - add an object to an object if key does not exist
• insert - inserts element
• update - updates a JSON object from another object, overwriting existing keys
• swap - exchanges the values

Lexicographical comparison operators

• operator== - comparison: equal
• operator!= - 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 - serialization
• to_string - user-defined to_string function for JSON values

Deserialization

• parse - deserialize from a compatible input
• accept - check if the input is valid JSON
• sax_parse - generate SAX events

Convenience functions

• type_name - return the type as string

JSON Pointer functions

• at - access specified object element with bounds checking via JSON Pointer
• operator[] - access specified element via JSON Pointer
• value - access specified object element with default value via JSON Pointer
• flatten - return flattened JSON value
• unflatten - unflatten a previously flattened JSON value

JSON Patch functions

• patch - applies a JSON patch
• diff (static) - creates a diff as a JSON patch

JSON Merge Patch functions

• merge_patch - applies a JSON Merge Patch

Static functions

• meta - returns version information on the library
• get_allocator - returns the allocator associated with the container

Binary formats

• to_cbor - create a CBOR serialization of a given JSON value
• to_msgpack - create a MessagePack serialization of a given JSON value
• to_ubjson - create a UBJSON serialization of a given JSON value
• to_bson - create a BSON serialization of a given JSON value
• from_cbor - create a JSON value from an input in CBOR format
• from_msgpack - create a JSON value from an input in MessagePack format
• from_ubjson - create a JSON value from an input in UBJSON format
• from_bson - create a JSON value from an input in BSON format

Non-member functions

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

Literals

• operator""_json
• operator""_json_pointer

Helper classes

• std::hashnlohmann::json\
• std::lessnlohmann::value_t\
• std::swapnlohmann::json\