Example Node.js glTF conversion script, using three.js.

FOO2GLTF.js

#!/usr/bin/env node

const fs = require('fs');
const path = require('path');
const THREE = require('three');
const program = require('commander');
const Canvas = require('canvas');
const { Blob, FileReader } = require('vblob');

// Patch global scope to imitate browser environment.
global.window = global;
global.Blob = Blob;
global.FileReader = FileReader;
global.THREE = THREE;
global.document = {
  createElement: (nodeName) => {
    if (nodeName !== 'canvas') throw new Error(`Cannot create node ${nodeName}`);
    const canvas = new Canvas(256, 256);
    // This isn't working — currently need to avoid toBlob(), so export to embedded .gltf not .glb.
    // canvas.toBlob = function () {
    //   return new Blob([this.toBuffer()]);
    // };
    return canvas;
  }
};

// https://github.com/mrdoob/three.js/issues/9562
require('three/examples/js/exporters/GLTFExporter');

program
  .version('0.0.1')
  .usage('[options] <file>')
  .option('-o, --output <file>', 'output filename', String)
  // .option('-b, --binary', 'use binary (.glb) format (default false)')
  .option('-m, --myoption', 'my custom option (default 1.0)', Number)
  .parse(process.argv);

program.binary = !!program.binary;
program.myoption = program.myoption || 1;

const inputPath = program.args[0];
if (!inputPath) { program.help(); }

if (!program.output) {
  program.output = path.basename(inputPath, '.foo');
  program.output += program.binary ? '.glb' : '.gltf';
}

console.log(' → input: %j', program.args);
console.log(' → output: %j', program.output);
console.log(' → binary: %j', program.binary);
console.log(' → my custom option: %j', program.myoption);

console.log(`Loading "${inputPath}"`);
let mesh = new THREE.Mesh(...); // (load or create mesh here)

console.log('Converting to glTF');
const exporter = new THREE.GLTFExporter();
exporter.parse(mesh, (content) => {

  console.log(`Writing to ${program.output}`);
  if (typeof content === 'object') content = JSON.stringify(content);
  fs.writeFileSync(program.output, content);

}, {binary: program.binary});

Hi. I was able to reduce it a little bit further:

Foo2Gltf.mjs:

import { writeFileSync } from 'fs';
import { basename } from 'path';
import { GLTFExporter }  from 'three/examples/jsm/exporters/GLTFExporter.js'
import { FileReader } from 'vblob';

// Patch global scope to imitate browser environment.
global.FileReader = FileReader;

const exportMeshToGLTF = (mesh, outputPath, options = { binary: false }) => {
  // Create an instance of the GLTFExporter
  const exporter = new GLTFExporter();

  // Define the output file name
  let output = outputPath;
  if (!output) {
    output = basename('output', '.foo');
    output += options.binary ? '.glb' : '.gltf';
  }

  console.log('Converting to glTF');
  exporter.parse(
    mesh,
    (content) => {
      console.log(`Writing to ${output}`);
      if (typeof content === 'object') content = JSON.stringify(content);
      writeFileSync(output, content);
      console.log('GLTF file has been saved.');
    },
    options
  );
};

export default exportMeshToGLTF;

and usage is:

index.mjs:

import { MeshBasicMaterial, BoxGeometry, Mesh } from 'three'
import exportMeshToGLTF from './Foo2Gltf.mjs';

// Create a geometry, for example, a box geometry
const geometry = new BoxGeometry();
const material = new MeshBasicMaterial({ color: 0x00ff00 });
const mesh = new Mesh(geometry, material);

exportMeshToGLTF(mesh, "cube.gltf")