Wrong Type Inference on React Native project in TypeScript: timePrecision prop type is wrong

[chinomnsoawazie]

What is happening?

In a ReactNative typescript project, the type inferred for MapViewDirections prop named timePrecison is MapViewDirectionsPrecision which is defined thus;

type MapViewDirectionsPrecision =
    | "high"
    | "low";

The accepted values in Google Directions API are now and none, which match the type declaration for MapViewDirectionsTimePrecision

      | "now"
      | "none";

Hence, when timePrecision is set to high or low, it incorrectly infers it as the right type. However, at runtime, the following error is thrown

MapViewDirections Error: Error on GMAPS route request: Invalid request. Invalid 'departure_time' parameter.

When when timePrecision is set to now or none, it incorrectly infers it as the wrong type.

Expected

The type inferred for MapViewDirections prop named timePrecison should be MapViewDirectionsTimePrecision

      | "now"
      | "none";

Then the right type is manually edited in the types definition file, it infers the type for timePrecision correctly

Screenshots

Correct props labeled as incorrect

Incorrect props labeled as correct

When the right type is manually edited into the type definition