Classes

Declare a class with class Name { ... }. Methods inside a class omit the fun keyword: just name(args) { }. Methods may use ...rest as the last parameter to collect trailing arguments into an array.

An init method runs when you call the class like a function. Use this for the current instance.

Instance fields are set with this.field = value. Reading undefined fields looks up methods on the class.

When a reference might be nil, use **?.** optional chaining to read nested fields without crashing. See **Optional chaining**.

class Greeter {
  init(name) {
    this.name = name;
  }

  hello() {
    print "Hello, " + this.name + "!";
  }
}

var g = Greeter("Rain");
g.hello();

Hello, Rain!

class Box {
  init(label) {
    this.label = label;
  }
}

var b = Box("gift");
print b.label;

gift