E0228: TypeScript optional properties are not allowed in JavaScript code
? on class properties is a TypeScript feature. It is a syntax error to write
? on a property in JavaScript code:
class Entity {
parent? = null;
}
To fix this error, erase the ?:
class Entity {
parent = null;
}
Alternatively, rename your file to have a .ts or .tsx suffix
Introduced in quick-lint-js version 2.6.0.