GLTFExporter: add onError parameter to parse

[marcofugaro]

Related issue: #22755 (comment)

Description

This allows us to correctly catch errors, even in the promise after this.pending.

I did this by converting GLTFWriter.write() to async since it was cleaner.

[Mugen87]

This change introduces a syntax error which breaks the exporter:

Uncaught SyntaxError: Identifier 'options' has already been declared

https://raw.githack.com/marcofugaro/three.js/gltfexporter-errors/examples/misc_exporter_gltf.html

[marcofugaro]

Ups, thanks for checking!

Fixed now.

[Mugen87]

It seems the documentation page also needs a small update: https://threejs.org/docs/index.html#examples/en/exporters/GLTFExporter

[marcofugaro]

Okay, will do. What should this example become?

Is it okay like this?

// Parse the input and generate the glTF output
exporter.parse(
  scene,
  // called when the gltf has been generated
  function ( gltf ) {
    console.log( gltf );
    downloadJSON( gltf );
  },
  // called when there are some error in the generations
  function ( error ) {
    console.log( 'An error happened' );
  },
  options
);

Otherwise I can just put null instead of the function.

[Mugen87]

Is it okay like this?

That looks good to me!

[marcofugaro]

Cool, all done.

[mrdoob]

Thanks!