in operator is not supported

Rule arkts-no-in

Severity: error

ArkTS does not support the operator in. However, this operator makes little sense since the object layout is known at compile time, and cannot be modified at runtime. Use instanceof as a workaround if you still need to check whether certain class members exist.

TypeScript

    class Person {
        name: string = ""
    }
    let p = new Person()

    let b = "name" in p // true

ArkTS

    class Person {
        name: string = ""
    }
    let p = new Person()

    let b = p instanceof Person // true, and "name" is guaranteed to be present

See also

• Recipe 001: Objects with property names that are not identifiers are not supported (arkts-identifiers-as-prop-names)
• Recipe 002: Symbol() API is not supported (arkts-no-symbol)
• Recipe 029: Indexed access is not supported for fields (arkts-no-props-by-index)
• Recipe 059: delete operator is not supported (arkts-no-delete)
• Recipe 060: typeof operator is allowed only in expression contexts (arkts-no-type-query)
• Recipe 144: Usage of standard library is restricted (arkts-limited-stdlib)