Function update

3rd/nlohmann_json/include/nlohmann/json.hpp:6000–6026

! @brief updates a JSON object from another object, overwriting existing keys Inserts all values from JSON object @a j and overwrites existing keys. @param[in] j JSON object to read values from @throw type_error.312 if called on JSON values other than objects; example: `"cannot use update() with string"` @complexity O(N*log(size() + N)), where N is the number of elemen

    @since version 3.0.0
    */
    void update(const_reference j)
    {
        // implicitly convert null value to an empty object
        if (is_null())
        {
            m_type = value_t::object;
            m_value.object = create<object_t>();
            assert_invariant();
        }

        if (JSON_HEDLEY_UNLIKELY(!is_object()))
        {
            JSON_THROW(type_error::create(312, "cannot use update() with " + std::string(type_name()), *this));
        }
        if (JSON_HEDLEY_UNLIKELY(!j.is_object()))
        {
            JSON_THROW(type_error::create(312, "cannot use update() with " + std::string(j.type_name()), *this));
        }

        for (auto it = j.cbegin(); it != j.cend(); ++it)
        {
            m_value.object->operator[](it.key()) = it.value();
#if JSON_DIAGNOSTICS
            m_value.object->operator[](it.key()).m_parent = this;
#endif
        }
    }

    /*!
    @brief updates a JSON object from another object, overwriting existing keys