Json.to

template<typename T, typename D = Nul>
requires convertible<Json, T> || convertible_map<Json, T, D> || convertible_array<Json, T, D>
T  to( D default_range_elem = D{} ) const;

Performs a type conversion (copy) of internal data to type T, throwing an exception if conversion fails.

Extensive compile-time type checking is performed - incompatible branches are eliminated during compilation.
However, conversion may still fail at runtime due to JSON's dynamic typing nature.

Conversion Rules

1. Nul → Nul
2. Obj → Obj
3. Arr → Arr
4. Str → Str
5. Bol → Bol
6. Num → Enum (rounded to nearest integer)
7. Num → Integer types (rounded)
8. Num → Floating-point types
9. Any → Types with Json constructors
10. Obj → Implicitly convertible types
11. Arr → Implicitly convertible types
12. Str → Implicitly convertible types
13. Num → Implicitly convertible types
14. Bol → Implicitly convertible types
15. Nul → Implicitly convertible types (except bool)
16. Obj → Convertible key-value types (element-wise)
17. Arr → Convertible container types (element-wise)
18. Throws std::runtime_error

Parameters

• T: Target type
• default_range_elem: Fallback value for failed element conversions (array/object only)

Exception Safety

Throws on conversion failure

Complexity

Linear time O(n) (full copy required)

Version

Since v3.0.0 .