The type definitions in @types/long define a type constructor like this:

new( low: number, high?: number, unsigned?: boolean ): Long;

The optional height allows users to write new Long(123). This is a problem as it makes it way too easy for callers to assume this is the correct number to Long conversion because it works for a very long time until it breaks.

The README marks heigh as required. The implementation works fine if unset because undefined | 0 is 0.

Is it safe to assume heigh is required and this can be considered a bug in the types?