Iso<A extends Object?, B extends Object?> class final

An isomorphism: a reversible transformation between two types.

An Iso represents a bidirectional mapping between types A and B. It consists of two inverse functions:

• to: transforms from A to B
• from: transforms from B to A

These functions form an isomorphism, meaning they are perfect inverses of each other: from(to(a)) == a and to(from(b)) == b for all valid values. This property is assumed but not enforced by the type system.

Use cases:

• Type conversions with guaranteed round-trip safety
• Bidirectional serialization/deserialization
• Format conversions (e.g., JSON ↔ Dart objects)
• Domain modeling (e.g., string representations ↔ enums)

Example:

// Define an isomorphism between String and int
final stringToInt = Iso(
  to: (s) => int.parse(s),
  from: (i) => i.toString(),
);

// Use it
assert(stringToInt.to('30') == 30);
assert(stringToInt.from(30) == '30');
assert(stringToInt.from(stringToInt.to('30')) == '30'); // Round-trip

Annotations

• @experimental

Constructors

Iso({required B to(A), required A from(B)})

Creates an isomorphism with the given to and from transformations.

const

Properties

asLens → Lens<A, B>

Downgrades this isomorphism to a Lens.

no setter

from → A Function(B)

Transforms a value from type B to type A.

final

hashCode → int

The hash code for this object.

no setter, inherited

inverse → Iso<B, A>

Flips the direction of this isomorphism.

no setter

isoList → Iso<List<A>, List<B>>

Lifts this isomorphism to work on lists of values.

no setter

runtimeType → Type

A representation of the runtime type of the object.

no setter, inherited

to → B Function(A)

Transforms a value from type A to type B.

final

Methods

noSuchMethod(Invocation invocation) → dynamic

Invoked when a nonexistent method or property is accessed.

inherited

then<C>(Iso<B, C> other) → Iso<A, C>

Composes this isomorphism with another isomorphism.

toString() → String

A string representation of this object.

inherited

Operators

operator ==(Object other) → bool

The equality operator.

inherited