# E0216: TypeScript interface properties cannot be 'static'

TypeScript interfaces describe objects (instances), not classes. It is a syntax error to create a static (class) property in an interface:

    interface Clock {
      static now(): number;
    };

    class SlowClock implements Clock {
      static now(): number {
        return Date.now() / 10;
      }
    }

To fix this error, make the property non-static and apply the interface to the class itself (not on instances):

    interface Clock {
      now(): number;
    };

    const SlowClock: Clock = class SlowClock {
      static now(): number {
        return Date.now() / 10;
      }
    };

Introduced in quick-lint-js version 2.6.0.

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