When BigNumber is imported into TypeScript projects at least once, it pollutes the namespace and allows for usage without importing in other files. This is fine when used just as a type, but causes runtime errors if used such as const x = new BigNumber(1); These runtime errors are not caught by linting / typecheck.

This behavior is not present in the decimal.js package.

See this minimal reproducible example here. This is a nextjs hello world app with decimal.js and bignumber.js imported, and shows how the latter pollutes the namespace.

Issue #143 ran into a similar issue – apparently it was fixed, but perhaps not fully or the concerning behavior returned.

UPDATE (see below): next.js build catches the missing import, but React Native Expo build does not.