Examples: Convert loaders to ES6 Part III.

[Mugen87]

Related issue: -

Description

More loader conversions.

I did not convert all loader to code to let/const since some code depends on the specific scoping of var. Since I'm not 100% familiar with the format of the following loaders, I would like to ask other devs for help and remove the remaining usage of var in 3DMLoader, EXRLoader, GCodeLoader, VTKLoader and LDrawLoader.

/ping @tentone, @yomboprime, @fraguada, @sciecode

[yomboprime]

I've tested the LDrawLoader exhaustively (all models and options) and seems to be working right.

[mrdoob]

Thanks!

[Mugen87]

What I have meant is that there is still code in the above loaders using var that needs to be converted.

[tentone]

Looks okay, On the GCodeLoader we can replace all var with let without problem.

[Mugen87]

@tentone Unfortunately that did not work in GCodeLoader. At the following place the linter says line is not defined when using let/const.

three.js/examples/jsm/loaders/GCodeLoader.js

Line 94 in 8f6cc7d

if ( line.extruding ) {

The entire function addSegment() should be refactored so it does not rely on variables outside its scope. There are few places in the code base where such changes are necessary.

[Mugen87]

This is another confusing place:

three.js/examples/jsm/loaders/GCodeLoader.js

Lines 202 to 211 in 8f6cc7d

	function addObject( vertex, extruding ) {
	var geometry = new BufferGeometry();
	geometry.setAttribute( 'position', new Float32BufferAttribute( vertex, 3 ) );
	var segments = new LineSegments( geometry, extruding ? extrudingMaterial : pathMaterial );
	segments.name = 'layer' + i;
	object.add( segments );
	}

Where does i come from? There are multiple loops in the outer function and it's hard to understand which i is valid in addObject().

[tentone]

The methods should be moved into the loop. i variable comes from there, I will create a branch and open a PR too clean these up.

Thanks a lot!

[mrdoob]

@Mugen87 @marcofugaro do you guys get this when running npm run build-examples?

[Mugen87]

I had the same error lately because of an outdated rollup version. Run npm i and try it again.

[mrdoob]

That was it. Thanks!

[fraguada]

@Mugen87 starting to look at this now to fix the remaining var. Thanks!