Dart Basic Tutorials

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Dart Basic Tutorials

https://dart.dev/guides/language/language-tour

final & const

https://dart.dev/guides/language/language-tour#final-and-const

final name = 'Bob'; 

// type annotation
final String nickname = 'Bobby';

https://dart.dev/guides/language/language-tour#initializer-list

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final timestamp = new DateTime.now().millisecondsSinceEpoch;
// 正确, 可以使用变量初始化赋值

const timestamp = new DateTime.now().millisecondsSinceEpoch; 
// 错误，不可以使用变量初始化赋值，必须使用常量初始化赋值
// 编译前报错：Const variables must be initialized with a constant value