meta library
Annotations that developers can use to express the intentions that otherwise can't be deduced by statically analyzing the source code.
See also @deprecated and @override in the dart:core
library.
Annotations provide semantic information that tools can use to provide a
better user experience. For example, an IDE might not autocomplete the name
of a function that's been marked @deprecated
, or it might display the
function's name differently.
For information on installing and importing this library, see the meta package on pub.dev. To learn more about using annotations, check out the Metadata documentation.
Classes
Constants
- alwaysThrows → const _AlwaysThrows
-
Used to annotate a function
f
. Indicates thatf
always throws an exception. Any functions that overridef
, in class inheritance, are also expected to conform to this contract. - checked → const _Checked
- Used to annotate a parameter of an instance method that overrides another method.
- doNotStore → const _DoNotStore
-
Used to annotate a method, getter, top-level function, or top-level getter
to indicate that the value obtained by invoking it should not be stored in a
field or top-level variable. The annotation can also be applied to a class
to implicitly annotate all of the valid members of the class, or applied to
a library to annotate all of the valid members of the library, including
classes. If a value returned by an element marked as
doNotStore
is returned from a function or getter, that function or getter should be similarly annotated. - doNotSubmit → const _DoNotSubmit
- Used to annotate an optional parameter, method, getter or top-level getter or function that is not intended to be accessed in checked-in code, but might be ephemerally used during development or local testing.
- experimental → const _Experimental
- Used to annotate a library, or any declaration that is part of the public interface of a library (such as top-level members, class members, and function parameters) to indicate that the annotated API is experimental and may be removed or changed at any-time without updating the version of the containing package, despite the fact that it would otherwise be a breaking change.
- factory → const _Factory
-
Used to annotate an instance or static method
m
. Indicates thatm
must either be abstract or must return a newly allocated object ornull
. In addition, every method that either implements or overridesm
is implicitly annotated with this same annotation. - immutable → const Immutable
-
Used to annotate a class
C
. Indicates thatC
and all subtypes ofC
must be immutable. - internal → const _Internal
- Used to annotate a declaration which should only be used from within the package in which it is declared, and which should not be exposed from said package's public API.
- isTest → const _IsTest
- Used to annotate a test framework function that runs a single test.
- isTestGroup → const _IsTestGroup
- Used to annotate a test framework function that runs a group of tests.
- literal → const _Literal
-
Used to annotate a const constructor
c
. Indicates that any invocation of the constructor must use the keywordconst
unless one or more of the arguments to the constructor is not a compile-time constant. - mustBeConst → const _MustBeConst
- Used to annotate a parameter which should be constant.
- mustBeOverridden → const _MustBeOverridden
-
Used to annotate an instance member
m
declared on a class or mixinC
. Indicates that every concrete subclass ofC
must directly overridem
. - mustCallSuper → const _MustCallSuper
-
Used to annotate an instance member (method, getter, setter, operator, or
field)
m
. Indicates that every invocation of a member that overridesm
must also invokem
. In addition, every method that overridesm
is implicitly annotated with this same annotation. - nonVirtual → const _NonVirtual
-
Used to annotate an instance member (method, getter, setter, operator, or
field)
m
in a classC
or mixinM
. Indicates thatm
should not be overridden in any classes that extend or mixinC
orM
. - optionalTypeArgs → const _OptionalTypeArgs
-
Used to annotate a class, mixin, extension, function, method, or typedef
declaration
C
. Indicates that any type arguments declared onC
are to be treated as optional. - protected → const _Protected
- Used to annotate an instance member in a class or mixin which is meant to be visible only within the declaring library, and to other instance members of the class or mixin, and their subtypes.
- redeclare → const _Redeclare
- Used to annotate an instance member of an extension type that redeclares a member from a superinterface.
- reopen → const _Reopen
-
Annotation for intentionally loosening restrictions on subtyping that would
otherwise cause lint warnings to be produced by the
implicit_reopen
lint. - required → const Required
-
Used to annotate a named parameter
p
in a method or functionf
. Indicates that every invocation off
must include an argument corresponding top
, despite the fact thatp
would otherwise be an optional parameter. - sealed → const _Sealed
- Annotation marking a class as not allowed as a super-type outside of the current package.
- useResult → const UseResult
- Used to annotate a method, field, or getter within a class, mixin, or extension, or a or top-level getter, variable or function to indicate that the value obtained by invoking it should be used. A value is considered used if it is assigned to a variable, passed to a function, or used as the target of an invocation, or invoked (if the result is itself a function).
- virtual → const _Virtual
- Used to annotate a field that is allowed to be overridden in Strong Mode.
- visibleForOverriding → const _VisibleForOverriding
- Used to annotate an instance member that was made public so that it could be overridden but that is not intended to be referenced from outside the defining library.
- visibleForTesting → const _VisibleForTesting
- Used to annotate a declaration that was made public, so that it is more visible than otherwise necessary, to make code testable.