First of all, the argument of fromInt() should be an Int, not an Int?. Trying to get a Type using null will obviously lead to null, and a caller shouldn’t even try doing that. The Map has also no reason to be mutable. The code can be reduced to: companion object { private val map … Read more
This is the JavaScript output of that enum: var MyEnum; (function (MyEnum) { MyEnum[MyEnum[“First”] = 0] = “First”; MyEnum[MyEnum[“Second”] = 1] = “Second”; MyEnum[MyEnum[“Third”] = 2] = “Third”; })(MyEnum || (MyEnum = {})); Which is an object like this: { “0”: “First”, “1”: “Second”, “2”: “Third”, “First”: 0, “Second”: 1, “Third”: 2 } Enum Members … Read more
Beginning 1.8, you can use enums like this: enum Fruit { apple, banana } main() { var a = Fruit.apple; switch (a) { case Fruit.apple: print(‘it is an apple’); break; } // get all the values of the enums for (List<Fruit> value in Fruit.values) { print(value); } // get the second value print(Fruit.values[1]); } The … Read more
Dart 2.7 comes with new feature called Extension methods. Now you can write your own methods for Enum as simple as that! enum Day { monday, tuesday } extension ParseToString on Day { String toShortString() { return this.toString().split(‘.’).last; } } main() { Day monday = Day.monday; print(monday.toShortString()); //prints ‘monday’ }
Not really. What I have seen is introducing a new struct for each enum variant, and then methods on the enum to decompose it: struct Dog(i32); struct Cat(u8); enum Animal { Dog(Dog), Cat(Cat), } impl Animal { fn cat(self) -> Cat { if let Animal::Cat(c) = self { c } else { panic!(“Not a cat”) … Read more
You can use the strum crate to easily iterate through the values of an enum. use strum::IntoEnumIterator; // 0.17.1 use strum_macros::EnumIter; // 0.17.1 #[derive(Debug, EnumIter)] enum Direction { NORTH, SOUTH, EAST, WEST, } fn main() { for direction in Direction::iter() { println!(“{:?}”, direction); } } Output: NORTH SOUTH EAST WEST
There are four different aspects to enums in TypeScript you need to be aware of. First, some definitions: “lookup object” If you write this enum: enum Foo { X, Y } TypeScript will emit the following object: var Foo; (function (Foo) { Foo[Foo[“X”] = 0] = “X”; Foo[Foo[“Y”] = 1] = “Y”; })(Foo || (Foo … Read more
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Though the answer is already provided, Almost no one pointed to the docs Here’s a snippet enum Enum { A } let nameOfA = Enum[Enum.A]; // “A” Keep in mind that string enum members do not get a reverse mapping generated at all.