ShaderNode: Remove .isArrayInput

[wcandillon]

Related issue: #27426

Description

We are running three.js on a JS engine (Hermes) wherefn.toString() does not return the source code of the function.
You can see a demo here: https://x.com/wcandillon/status/1825862686300672124
This is an alternative implementation of inputs that would fit.

I do have some question:

• I suspect that somewhere else in the code, inputs is checked with Array.isArray which will always return false (but it will not break the code). So there is probably more cleaning up that could be done here (I'm just not sure where).
• Running the build step adds formatting changes that seem unrelated to this change.
• The build files seem to contain unrelated changes as well.

Let me know what you think ☺️

[github-actions]

📦 Bundle size

Full ESM build, minified and gzipped.

Filesize dev	Filesize PR	Diff
685.4 kB (169.7 kB)	685.4 kB (169.7 kB)	+0 B

🌳 Bundle size after tree-shaking

Minimal build including a renderer, camera, empty scene, and dependencies.

Filesize dev	Filesize PR	Diff
462 kB (111.4 kB)	462 kB (111.4 kB)	+0 B

[wcandillon]

@sunag thank you for looking into it ☺️ This is my first PR in three.js

[sunag]

Thanks @wcandillon, this approach is much better. I hope this PR is the first of many PRs :)