使用extension on 关键字
main(List<String> args) { String a = 'tom'; print(a.hello()); } extension NumberParsing on String { String hello() { return 'hello ' + this; } }
main(List<String> args) { String a = 'tom'; print(a.hello()); } extension NumberParsing on String { String hello() { return 'hello ' + this; } }