TypeScript: Documentation - Decorators
https://www.typescriptlang.org/docs/handbook/decorators.html
Decorators. A Decorator is a special kind of declaration that can be attached to a class declaration, method, accessor, property, or parameter.Decorators use the form @expression, where expression must evaluate to a function that will be called at runtime with information about the decorated declaration.. For example, given the decorator @sealed we might write the sealed function as follows:
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