[DevTask] Explicit null vs undefined

[webfiltered]

Current

There are enough discussions on this topic, but as it pertains to Litegraph, the vast majority null usage in the library appears to be stylistic, rather than functional.

Strict typing in TypeScript becomes extremely verbose when null is used simply as a stand-in for idiomatic undefined. Worse still, it often requires runtime guards to guarantee type safety.

Proposed

Wherever null is used for indeterminate purposes, and could simply be replaced with undefined (or e.g. just not returning a value), it should be.

Prefer shorthand where appropriate, e.g. optional properties. Adding | undefined works for props/params that must be specified, but may not have a value.

Any use of explicit null where it is strict-equality checked can be ignored - it's serving some purpose or another. There are only a handful of instances, anyway.