= `object` A <<ref_value>> stores an instance of <<ref_object>> as the underlying representation for a JSON object. Instances of the <<ref_object>> type are associative containers holding key and value pairs, where the key is a <<ref_string_view>> and the mapped type is a <<ref_value>>. These containers are modelled after standard maps with these properties: The elements are stored contiguously as instances of <<ref_key_value_pair>>. Iterators are ordinary pointers, and may become invalidated on insertions and removals. The order of insertions is preserved, as long as there are no removals. All inserted values will use the same {ref_memory_resource} as the container itself. An empty object may be constructed without incurring any memory allocations using the <<default_memory_resource,default memory resource>>. A <<ref_storage_ptr>> can also be explicitly specified: Initializer lists consisting of two-element key value pairs can be used to construct objects with initial contents. These constructors may allocate memory and throw: Alternatively, elements may be inserted after construction: Similar to the `std` counterpart, elements may be accessed directly by their key with bounds checking using <<ref_object_at>>, or without bounds checking using <<ref_object_operator_lb_rb>> which creates a null element if the key does not already exist: Internally, the container computes a hash table over the keys so that the complexity of lookups is in constant time, on average. For the complete listing of all available member functions and nested types, see the reference page for <<ref_object>>. As with `std::pair`, the <<ref_key_value_pair>> type can be used with structured bindings in {cpp}17. Specializations of `std::tuple_size`, `std::tuple_element`, and overloads of <<ref_get>> are all provided for this purpose. Formatted Output When an <<ref_object>> is formatted to a {std_ostream}, the result is a valid JSON. That is, the object will be output with curly braces and a comma separated list of key/value pairs, as per the JSON specification.