draco-encode-issue.js

import { Document, NodeIO } from '@gltf-transform/core';
import { DracoMeshCompression } from '@gltf-transform/extensions';
import * as draco3d from 'draco3dgltf';

export async function draco_encode_issue (useTimeout = false) {

    const doc = new Document();

    const buffer = doc.createBuffer('bin');

    const accessor = doc.createAccessor('positions')
        .setArray(new Float32Array([
            0, 0, 0,
            1, 0, 0,
            1, 1, 0
        ]))
        .setType(Accessor.Type.VEC3)
        .setBuffer(buffer);

    const indices = doc.createAccessor('indices')
        .setArray(new Uint16Array([0, 1, 2]))
        .setType(Accessor.Type.SCALAR)
        .setBuffer(buffer);

    const material = doc.createMaterial('material')
        .setBaseColorFactor([1, 0, 0, 1]);

    const primitive = doc.createPrimitive()
        .setAttribute('POSITION', accessor)
        .setIndices(indices)
        .setMaterial(material);

    const mesh = doc.createMesh('mesh')
        .addPrimitive(primitive);

    const node = doc.createNode('node')
        .setMesh(mesh);

    const scene = doc.createScene('scene')
        .addChild(node);

    doc.createExtension(DracoMeshCompression).setRequired(true);

    const io = new NodeIO()
        .registerExtensions([DracoMeshCompression])
        .registerDependencies({
            'draco3d.decoder': draco3d.createDecoderModule(),
            'draco3d.encoder': draco3d.createEncoderModule(),
        });

    if (useTimeout) {
        setTimeout(() => {
            io.write('draco_extension_issue.glb', doc);
        }, 1000);
    } else {
        // throws: "TypeError: Cannot read property 'apply' of undefined"
        io.write('draco_extension_issue.glb', doc);
    }
}