E0227: index signature must be a field, not a method
A TypeScript index signature describes a property. TypeScript only supports the field syntax for index signatures. It is a syntax error to write an index signature using method syntax:
interface EventTable {
[eventName: string](event: Event): void;
}
To fix this error, write the value type using function type syntax instead:
interface EventTable {
[eventName: string]: (event: Event) => void;
}
Introduced in quick-lint-js version 2.6.0.