show
If you want to selectively import part of the library.
async
To define an async function, a function marked as async.
sync
To implement a synchronous generator function, mark the function body as sync*.
on
Use on when you need to specify the exception type
hide
If you want to import all names EXCEPT some part of library.
These keywords are valid identifiers in most places, but they can’t be used as class or type names, or as import prefixes.
abstract
Use the abstract modifier to define an abstract class and abstract methods.
dynamic
Use dynamic keyword, when you want to explicitly say that no type is expected to an object.
implements
A class may implement a number of interfaces by declaring them in its implements clause.
as
Use the as operator to cast an object to a particular type if and only if you are sure that the object is of that type.
static
Use the static keyword to implement class-wide variables and methods.
import
Use import to specify how a namespace from one library is used in the scope of another library.
export
Use export to specify how a namespace of library is available to access in the scope of another library.
part
Use part directive, which allows you to split a library into multiple Dart files.
interface
The interface keyword was removed from Dart.
external
Used on functions, an external function is a function whose body is provided separately from its declaration.
library
A library directives can help you create a modular and shareable code base.
factory
Use the factory keyword when implementing a constructor that doesn’t always create a new instance of its class.
mixin
Mixins are a way of reusing a class’s code in multiple class hierarchies.
typedef
A typedef, or function-type alias, gives a function type a name that you can use
when declaring fields and return types.
operator
An overloaded operator is called an operator function. You declare an operator function with the keyword operator preceding the operator.
covariant
you can use the covariant keyword to tell the analyzer that you are intentionally tightening a type by overriding a parameter’s type with a subtype.
Function
Dart is a true object-oriented language, so even functions are objects and have a type, Function.
deferred
Deferred loading (also called lazy loading) allows a web app to load a library on demand, if and when the library is needed
set
Use set to provide write access to an object’s properties.
get
Use get to provide read access to an object’s properties.
Reserved words
if
Dart supports if statements
else
Define optional else statements.
switch
A switch statement is a type of selection control mechanism.
default
Use a default clause to execute code when no case clause matches.
break
A keyword used to used to stop looping.
continue
Use continue to skip to the next loop iteration.
for
You can iterate with the standard for loop
while
A while loop evaluates the condition before the loop.
return
The return statement returns a result to the caller of a synchronous function.
assert
Use an assert statement — assert(condition, optionalMessage); — to disrupt normal execution if a boolean condition is false.
enum
To declare an enumerated type using the enum keyword.
in
for-in used on Iterable classes.
super
super keyword is to refer to the superclass.
extends
Use extends to create a subclass.
is
If you aren’t sure that the object is of type T, then use is to check the type before using the object.
this
The this keyword refers to the current instance.
case
To specify a code block which needs to be executed.
new
A new keyword before the constructor name to create an object.
true
To represent boolean value
false
To represent boolean value.
class
Use to declare a class.
final
If you never intend to change a variable, use final.
const
If you never intend to change a variable, use const.
null
Uninitialized variables have an initial value of null.
var
creating a variable and initializing it.
void
Used at method declaration and definition to specify that the method does not return any type.
with
To use a mixin, use the with keyword followed by one or more mixin names.
do
A do-while loop evaluates the condition after the loop.
try
The try statement is definition of exception handling code in a structured way.
catch
Catching, or capturing, an exception.
finally
The finally keyword is to ensure that some code runs whether or not an exception is thrown.
throw
use to throw as exception.
rethrow
To partially handle an exception, while allowing it to propagate, use the rethrow keyword.
await
Uses await to wait for the result of an asynchronous function.
yield
Use yield statements to deliver values