Allow node-red to load nodes with .cjs file extension

[Pezmc]

• Bugfix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)

Fixes #4431

Updates the loader to no-longer assume that the node file always .js as a file extension for the javascript.

.cjs files work without issue, but previously node-red would try to load a template called file-name.cjs instead of file-name.html, which meant nodes would be missing from the palette despite showing as loaded in settings.

Templates failing to load are silently ignored, in case a node has no associated template, so no error would be displayed but there would be no front-end node available:

node-red/packages/node_modules/@node-red/registry/lib/loader.js

Lines 215 to 224 in 0589e1f

	}).catch(err => {
	// ENOENT means no html file. We can live with that. But any other error
	// should be fatal
	// node.err = "Error: "+node.template+" does not exist";
	node.types = node.types || [];
	if (err.code !== 'ENOENT') {
	node.err = err.toString();
	}
	return node;
	});

Before

For example node from #4431 (https://github.com/Pezmc/node-red-test-node)

After

Proposed changes

Checklist

• I have read the contribution guidelines
• For non-bugfix PRs, I have discussed this change on the forum/slack team.
• I have run npm run test to verify the unit tests pass
• [-] I have added suitable unit tests to cover the new/changed functionality - Seemingly no test coverage in this area

[knolleary]

Change looks good, however there is another place where we make this assumption/substitution.

• https://github.com/node-red/node-red/blob/master/packages/node_modules/%40node-red/registry/lib/localfilesystem.js#L75
• Same file lines 79 and 117

These code paths are related to loading 'bare' node files out of the ~/.node-red/nodes directory - ones that are not packaged as modules. It's a bit of an edge case, but then, so is using .cjs anyway ;)

[Pezmc]

I didn't find any usage (or test coverage) of getLocalFile in https://github.com/Pezmc/node-red/blob/4920611b69f124757f4c97b3f97c6f3fe7854f5c/packages/node_modules/@node-red/registry/lib/localfilesystem.js#L593 but I have updated it!

[Pezmc]

@knolleary Updated above, used a slightly closer guard to ensure only js files are checked.