mixins doesn't appear in the current doc website https://flow.org/en/docs/

but it was present in the doc at some point:

5c4297b

+  ## Mixins
+
+  You can declare a class which mixes in 1 or more other classes with the
+  `mixins` keyword. Mixing class `B` into class `A` copies `B`'s fields and
+  methods into `A`. Note, however, that any fields or methods that `B` inherits
+  are not copied over. Mixins are for code reuse, not for multiple inheritance.
+

mode examples in the diff

⚠️ BTW, the commit title says: "and adds a note about similarity to TypeScript and Dart." but there is no mention of TypeScript or Dart in the commit

some more infos about mixins can be found in commits:

448fcb3

interface and declare class share a lot of implementation details, but they also have a bunch of differences. their bodies are identical (for now, though it doesn't really make sense for an interface to have statics).

however, interface can have multiple extends, but no mixins; declare class can have mixins, but only one extends. interfaces' ids are types, classes' are also values.

12741b0

When processing a spec, if we see a mixins object, we resolve those in
turn (recursively, as mixins can have mixins), actually mix them in, then emit
the class type.

b72d1c6

Multiple inheritance is available via a new clause declaring 'mixins': declare class Foo extends Bar mixins Qux.

Document what mixins actually do #1383

Description

Metadata

Metadata

Assignees

Labels

Type

Projects

Milestone

Relationships

Development

Issue actions