instanceof operator is partially supported

Rule arkts-instanceof-ref-types

Severity: error

In TypeScript, the left-hand side of an instanceof expression must be of the type any, an object type or a type parameter; the result is false otherwise. In ArkTS, the left-hand side expression may be of any reference type; a compile-time error occurs otherwise. In addition, the left operand in ArkTS cannot be a type.

TypeScript

    class X {
        // ...
    }

    let a = (new X()) instanceof Object // true
    let b = (new X()) instanceof X      // true

    let c = X instanceof Object // true, left operand is a type
    let d = X instanceof X      // false, left operand is a type

ArkTS

    class X {
        // ...
    }

    let a = (new X()) instanceof Object // true
    let b = (new X()) instanceof X      // true

    let c = X instanceof Object // Compile-time error, left operand is a type
    let d = X instanceof X      // Compile-time error, left operand is a type