feat: Add input validation for use as a JS library

[bengourley]

Goal

When used via TypeScript, as we do in our commands, the uploader libraries have type information that prevent certain kinds of input. However, when used via JS – as is one of the use cases of this package – no such safety is in place. The goal is to add input checking at runtime to ensure early and helpful feedback to the user when invalid input is provided.

Design

I've implemented a set of reusable input checking functions. Each uploader has slightly different parameters that it supports so the exact validation method is composed of multiple calls to the input checkers specifying the kind of input allowed.

It also checks for unknown options, since this can (and has been) as source of confusion – for instance, passing bundleUrl into the Node uploader.

Changeset

• New lib/InputValidators.ts file
• Updated all of the node/browser/reactnative upload*() methods to first validate the provided input. If invalid input is detected, these functions will reject a promise with the validation error.

Testing

• Added test cases for all functions where the input validation was added.