typescript type_error ai_generated true

error TS2352: Conversion of type 'X' to type 'Y' may be a mistake

ID: typescript/ts2352-conversion-may-be-mistake

Also available as: JSON · Markdown
92%Fix Rate
92%Confidence
50Evidence
2023-01-01First Seen

Version Compatibility

VersionStatusIntroducedDeprecatedNotes
5 active — — —

Root Cause

Type assertion (as) between incompatible types. TypeScript warns the cast looks wrong.

generic

Workarounds

  1. 95% success Use type narrowing instead of assertion: instanceof, typeof, in operator 
    if (obj instanceof MyClass) { obj.method(); }

    Sources: https://www.typescriptlang.org/docs/handbook/2/narrowing.html

  2. 88% success Create a type guard function for complex narrowing 
    function isMyType(x: unknown): x is MyType { return 'key' in (x as object); }

    Sources: https://www.typescriptlang.org/docs/handbook/2/narrowing.html#using-type-predicates

  3. 90% success Fix the actual type mismatch instead of casting 
    // Instead of forcing a cast:
// const x = value as unknown as TargetType; // bad

// Fix the actual type:
function process(input: string): number {
  return parseInt(input, 10); // proper conversion
}

// Or use a type guard:
if (typeof value === 'string') {
  // TypeScript knows value is string here
}

    Sources: https://www.typescriptlang.org/docs/handbook/2/types-from-types.html

Dead Ends

Common approaches that don't work:

  1. Double cast: x as unknown as Y 75% fail

    Bypasses all type safety — any bug will be a runtime error

  2. Use any as intermediate 80% fail

    Same as double cast — loses all type information

Error Chain

Leads to:
Preceded by:
Frequently confused with: