parse( object, onDone, options = {} ) {

			options = Object.assign( {
				version: '1.4.1',
				author: null,
				textureDirectory: ''
			}, options );

			if ( options.textureDirectory !== '' ) {

				options.textureDirectory = `${options.textureDirectory}/`.replace( /\\/g, '/' ).replace( /\/+/g, '/' );

			}

			const version = options.version;

			if ( version !== '1.4.1' && version !== '1.5.0' ) {

				console.warn( `ColladaExporter : Version ${version} not supported for export. Only 1.4.1 and 1.5.0.` );
				return null;

			} // Convert the urdf xml into a well-formatted, indented format


			function format( urdf ) {

				const IS_END_TAG = /^<\//;
				const IS_SELF_CLOSING = /(\?>$)|(\/>$)/;
				const HAS_TEXT = /<[^>]+>[^<]*<\/[^<]+>/;

				const pad = ( ch, num ) => num > 0 ? ch + pad( ch, num - 1 ) : '';

				let tagnum = 0;
				return urdf.match( /(<[^>]+>[^<]+<\/[^<]+>)|(<[^>]+>)/g ).map( tag => {

					if ( ! HAS_TEXT.test( tag ) && ! IS_SELF_CLOSING.test( tag ) && IS_END_TAG.test( tag ) ) {

						tagnum --;

					}

					const res = `${pad( '  ', tagnum )}${tag}`;

					if ( ! HAS_TEXT.test( tag ) && ! IS_SELF_CLOSING.test( tag ) && ! IS_END_TAG.test( tag ) ) {

						tagnum ++;

					}

					return res;

				} ).join( '\n' );

			} // Convert an image into a png format for saving


			function base64ToBuffer( str ) {

				const b = atob( str );
				const buf = new Uint8Array( b.length );

				for ( let i = 0, l = buf.length; i < l; i ++ ) {

					buf[ i ] = b.charCodeAt( i );

				}

				return buf;

			}

			let canvas, ctx;

			function imageToData( image, ext ) {

				canvas = canvas || document.createElement( 'canvas' );
				ctx = ctx || canvas.getContext( '2d' );
				canvas.width = image.width;
				canvas.height = image.height;
				ctx.drawImage( image, 0, 0 ); // Get the base64 encoded data

				const base64data = canvas.toDataURL( `image/${ext}`, 1 ).replace( /^data:image\/(png|jpg);base64,/, '' ); // Convert to a uint8 array

				return base64ToBuffer( base64data );

			} // gets the attribute array. Generate a new array if the attribute is interleaved


			const getFuncs = [ 'getX', 'getY', 'getZ', 'getW' ];

			function attrBufferToArray( attr ) {

				if ( attr.isInterleavedBufferAttribute ) {

					// use the typed array constructor to save on memory
					const arr = new attr.array.constructor( attr.count * attr.itemSize );
					const size = attr.itemSize;

					for ( let i = 0, l = attr.count; i < l; i ++ ) {

						for ( let j = 0; j < size; j ++ ) {

							arr[ i * size + j ] = attr[ getFuncs[ j ] ]( i );

						}

					}

					return arr;

				} else {

					return attr.array;

				}

			} // Returns an array of the same type starting at the `st` index,
			// and `ct` length


			function subArray( arr, st, ct ) {

				if ( Array.isArray( arr ) ) return arr.slice( st, st + ct ); else return new arr.constructor( arr.buffer, st * arr.BYTES_PER_ELEMENT, ct );

			} // Returns the string for a geometry's attribute


			function getAttribute( attr, name, params, type ) {

				const array = attrBufferToArray( attr );
				const res = `<source id="${name}">` + `<float_array id="${name}-array" count="${array.length}">` + array.join( ' ' ) + '</float_array>' + '<technique_common>' + `<accessor source="#${name}-array" count="${Math.floor( array.length / attr.itemSize )}" stride="${attr.itemSize}">` + params.map( n => `<param name="${n}" type="${type}" />` ).join( '' ) + '</accessor>' + '</technique_common>' + '</source>';
				return res;

			} // Returns the string for a node's transform information


			let transMat;

			function getTransform( o ) {

				// ensure the object's matrix is up to date
				// before saving the transform
				o.updateMatrix();
				transMat = transMat || new THREE.Matrix4();
				transMat.copy( o.matrix );
				transMat.transpose();
				return `<matrix>${transMat.toArray().join( ' ' )}</matrix>`;

			} // Process the given piece of geometry into the geometry library
			// Returns the mesh id


			function processGeometry( g ) {

				let info = geometryInfo.get( g );

				if ( ! info ) {

					// convert the geometry to bufferGeometry if it isn't already
					const bufferGeometry = g;

					if ( bufferGeometry.isBufferGeometry !== true ) {

						throw new Error( 'THREE.ColladaExporter: Geometry is not of type THREE.BufferGeometry.' );

					}

					const meshid = `Mesh${libraryGeometries.length + 1}`;
					const indexCount = bufferGeometry.index ? bufferGeometry.index.count * bufferGeometry.index.itemSize : bufferGeometry.attributes.position.count;
					const groups = bufferGeometry.groups != null && bufferGeometry.groups.length !== 0 ? bufferGeometry.groups : [ {
						start: 0,
						count: indexCount,
						materialIndex: 0
					} ];
					const gname = g.name ? ` name="${g.name}"` : '';
					let gnode = `<geometry id="${meshid}"${gname}><mesh>`; // define the geometry node and the vertices for the geometry

					const posName = `${meshid}-position`;
					const vertName = `${meshid}-vertices`;
					gnode += getAttribute( bufferGeometry.attributes.position, posName, [ 'X', 'Y', 'Z' ], 'float' );
					gnode += `<vertices id="${vertName}"><input semantic="POSITION" source="#${posName}" /></vertices>`; // NOTE: We're not optimizing the attribute arrays here, so they're all the same length and
					// can therefore share the same triangle indices. However, MeshLab seems to have trouble opening
					// models with attributes that share an offset.
					// MeshLab Bug#424: https://sourceforge.net/p/meshlab/bugs/424/
					// serialize normals

					let triangleInputs = `<input semantic="VERTEX" source="#${vertName}" offset="0" />`;

					if ( 'normal' in bufferGeometry.attributes ) {

						const normName = `${meshid}-normal`;
						gnode += getAttribute( bufferGeometry.attributes.normal, normName, [ 'X', 'Y', 'Z' ], 'float' );
						triangleInputs += `<input semantic="NORMAL" source="#${normName}" offset="0" />`;

					} // serialize uvs


					if ( 'uv' in bufferGeometry.attributes ) {

						const uvName = `${meshid}-texcoord`;
						gnode += getAttribute( bufferGeometry.attributes.uv, uvName, [ 'S', 'T' ], 'float' );
						triangleInputs += `<input semantic="TEXCOORD" source="#${uvName}" offset="0" set="0" />`;

					} // serialize lightmap uvs


					if ( 'uv2' in bufferGeometry.attributes ) {

						const uvName = `${meshid}-texcoord2`;
						gnode += getAttribute( bufferGeometry.attributes.uv2, uvName, [ 'S', 'T' ], 'float' );
						triangleInputs += `<input semantic="TEXCOORD" source="#${uvName}" offset="0" set="1" />`;

					} // serialize colors


					if ( 'color' in bufferGeometry.attributes ) {

						const colName = `${meshid}-color`;
						gnode += getAttribute( bufferGeometry.attributes.color, colName, [ 'X', 'Y', 'Z' ], 'uint8' );
						triangleInputs += `<input semantic="COLOR" source="#${colName}" offset="0" />`;

					}

					let indexArray = null;

					if ( bufferGeometry.index ) {

						indexArray = attrBufferToArray( bufferGeometry.index );

					} else {

						indexArray = new Array( indexCount );

						for ( let i = 0, l = indexArray.length; i < l; i ++ ) indexArray[ i ] = i;

					}

					for ( let i = 0, l = groups.length; i < l; i ++ ) {

						const group = groups[ i ];
						const subarr = subArray( indexArray, group.start, group.count );
						const polycount = subarr.length / 3;
						gnode += `<triangles material="MESH_MATERIAL_${group.materialIndex}" count="${polycount}">`;
						gnode += triangleInputs;
						gnode += `<p>${subarr.join( ' ' )}</p>`;
						gnode += '</triangles>';

					}

					gnode += '</mesh></geometry>';
					libraryGeometries.push( gnode );
					info = {
						meshid: meshid,
						bufferGeometry: bufferGeometry
					};
					geometryInfo.set( g, info );

				}

				return info;

			} // Process the given texture into the image library
			// Returns the image library


			function processTexture( tex ) {

				let texid = imageMap.get( tex );

				if ( texid == null ) {

					texid = `image-${libraryImages.length + 1}`;
					const ext = 'png';
					const name = tex.name || texid;
					let imageNode = `<image id="${texid}" name="${name}">`;

					if ( version === '1.5.0' ) {

						imageNode += `<init_from><ref>${options.textureDirectory}${name}.${ext}</ref></init_from>`;

					} else {

						// version image node 1.4.1
						imageNode += `<init_from>${options.textureDirectory}${name}.${ext}</init_from>`;

					}

					imageNode += '</image>';
					libraryImages.push( imageNode );
					imageMap.set( tex, texid );
					textures.push( {
						directory: options.textureDirectory,
						name,
						ext,
						data: imageToData( tex.image, ext ),
						original: tex
					} );

				}

				return texid;

			} // Process the given material into the material and effect libraries
			// Returns the material id


			function processMaterial( m ) {

				let matid = materialMap.get( m );

				if ( matid == null ) {

					matid = `Mat${libraryEffects.length + 1}`;
					let type = 'phong';

					if ( m.isMeshLambertMaterial === true ) {

						type = 'lambert';

					} else if ( m.isMeshBasicMaterial === true ) {

						type = 'constant';

						if ( m.map !== null ) {

							// The Collada spec does not support diffuse texture maps with the
							// constant shader type.
							// mrdoob/three.js#15469
							console.warn( 'ColladaExporter: Texture maps not supported with THREE.MeshBasicMaterial.' );

						}

					}

					const emissive = m.emissive ? m.emissive : new THREE.Color( 0, 0, 0 );
					const diffuse = m.color ? m.color : new THREE.Color( 0, 0, 0 );
					const specular = m.specular ? m.specular : new THREE.Color( 1, 1, 1 );
					const shininess = m.shininess || 0;
					const reflectivity = m.reflectivity || 0; // Do not export and alpha map for the reasons mentioned in issue (#13792)
					// in three.js alpha maps are black and white, but collada expects the alpha
					// channel to specify the transparency

					let transparencyNode = '';

					if ( m.transparent === true ) {

						transparencyNode += '<transparent>' + ( m.map ? '<texture texture="diffuse-sampler"></texture>' : '<float>1</float>' ) + '</transparent>';

						if ( m.opacity < 1 ) {

							transparencyNode += `<transparency><float>${m.opacity}</float></transparency>`;

						}

					}

					const techniqueNode = `<technique sid="common"><${type}>` + '<emission>' + ( m.emissiveMap ? '<texture texture="emissive-sampler" texcoord="TEXCOORD" />' : `<color sid="emission">${emissive.r} ${emissive.g} ${emissive.b} 1</color>` ) + '</emission>' + ( type !== 'constant' ? '<diffuse>' + ( m.map ? '<texture texture="diffuse-sampler" texcoord="TEXCOORD" />' : `<color sid="diffuse">${diffuse.r} ${diffuse.g} ${diffuse.b} 1</color>` ) + '</diffuse>' : '' ) + ( type !== 'constant' ? '<bump>' + ( m.normalMap ? '<texture texture="bump-sampler" texcoord="TEXCOORD" />' : '' ) + '</bump>' : '' ) + ( type === 'phong' ? `<specular><color sid="specular">${specular.r} ${specular.g} ${specular.b} 1</color></specular>` + '<shininess>' + ( m.specularMap ? '<texture texture="specular-sampler" texcoord="TEXCOORD" />' : `<float sid="shininess">${shininess}</float>` ) + '</shininess>' : '' ) + `<reflective><color>${diffuse.r} ${diffuse.g} ${diffuse.b} 1</color></reflective>` + `<reflectivity><float>${reflectivity}</float></reflectivity>` + transparencyNode + `</${type}></technique>`;
					const effectnode = `<effect id="${matid}-effect">` + '<profile_COMMON>' + ( m.map ? '<newparam sid="diffuse-surface"><surface type="2D">' + `<init_from>${processTexture( m.map )}</init_from>` + '</surface></newparam>' + '<newparam sid="diffuse-sampler"><sampler2D><source>diffuse-surface</source></sampler2D></newparam>' : '' ) + ( m.specularMap ? '<newparam sid="specular-surface"><surface type="2D">' + `<init_from>${processTexture( m.specularMap )}</init_from>` + '</surface></newparam>' + '<newparam sid="specular-sampler"><sampler2D><source>specular-surface</source></sampler2D></newparam>' : '' ) + ( m.emissiveMap ? '<newparam sid="emissive-surface"><surface type="2D">' + `<init_from>${processTexture( m.emissiveMap )}</init_from>` + '</surface></newparam>' + '<newparam sid="emissive-sampler"><sampler2D><source>emissive-surface</source></sampler2D></newparam>' : '' ) + ( m.normalMap ? '<newparam sid="bump-surface"><surface type="2D">' + `<init_from>${processTexture( m.normalMap )}</init_from>` + '</surface></newparam>' + '<newparam sid="bump-sampler"><sampler2D><source>bump-surface</source></sampler2D></newparam>' : '' ) + techniqueNode + ( m.side === THREE.DoubleSide ? '<extra><technique profile="THREEJS"><double_sided sid="double_sided" type="int">1</double_sided></technique></extra>' : '' ) + '</profile_COMMON>' + '</effect>';
					const materialName = m.name ? ` name="${m.name}"` : '';
					const materialNode = `<material id="${matid}"${materialName}><instance_effect url="#${matid}-effect" /></material>`;
					libraryMaterials.push( materialNode );
					libraryEffects.push( effectnode );
					materialMap.set( m, matid );

				}

				return matid;

			} // Recursively process the object into a scene


			function processObject( o ) {

				let node = `<node name="${o.name}">`;
				node += getTransform( o );

				if ( o.isMesh === true && o.geometry !== null ) {

					// function returns the id associated with the mesh and a "BufferGeometry" version
					// of the geometry in case it's not a geometry.
					const geomInfo = processGeometry( o.geometry );
					const meshid = geomInfo.meshid;
					const geometry = geomInfo.bufferGeometry; // ids of the materials to bind to the geometry

					let matids = null;
					let matidsArray; // get a list of materials to bind to the sub groups of the geometry.
					// If the amount of subgroups is greater than the materials, than reuse
					// the materials.

					const mat = o.material || new THREE.MeshBasicMaterial();
					const materials = Array.isArray( mat ) ? mat : [ mat ];

					if ( geometry.groups.length > materials.length ) {

						matidsArray = new Array( geometry.groups.length );

					} else {

						matidsArray = new Array( materials.length );

					}

					matids = matidsArray.fill().map( ( v, i ) => processMaterial( materials[ i % materials.length ] ) );
					node += `<instance_geometry url="#${meshid}">` + ( matids != null ? '<bind_material><technique_common>' + matids.map( ( id, i ) => `<instance_material symbol="MESH_MATERIAL_${i}" target="#${id}" >` + '<bind_vertex_input semantic="TEXCOORD" input_semantic="TEXCOORD" input_set="0" />' + '</instance_material>' ).join( '' ) + '</technique_common></bind_material>' : '' ) + '</instance_geometry>';

				}

				o.children.forEach( c => node += processObject( c ) );
				node += '</node>';
				return node;

			}

			const geometryInfo = new WeakMap();
			const materialMap = new WeakMap();
			const imageMap = new WeakMap();
			const textures = [];
			const libraryImages = [];
			const libraryGeometries = [];
			const libraryEffects = [];
			const libraryMaterials = [];
			const libraryVisualScenes = processObject( object );
			const specLink = version === '1.4.1' ? 'http://www.collada.org/2005/11/COLLADASchema' : 'https://www.khronos.org/collada/';
			let dae = '<?xml version="1.0" encoding="UTF-8" standalone="no" ?>' + `<COLLADA xmlns="${specLink}" version="${version}">` + '<asset>' + ( '<contributor>' + '<authoring_tool>three.js Collada Exporter</authoring_tool>' + ( options.author !== null ? `<author>${options.author}</author>` : '' ) + '</contributor>' + `<created>${new Date().toISOString()}</created>` + `<modified>${new Date().toISOString()}</modified>` + '<up_axis>Y_UP</up_axis>' ) + '</asset>';
			dae += `<library_images>${libraryImages.join( '' )}</library_images>`;
			dae += `<library_effects>${libraryEffects.join( '' )}</library_effects>`;
			dae += `<library_materials>${libraryMaterials.join( '' )}</library_materials>`;
			dae += `<library_geometries>${libraryGeometries.join( '' )}</library_geometries>`;
			dae += `<library_visual_scenes><visual_scene id="Scene" name="scene">${libraryVisualScenes}</visual_scene></library_visual_scenes>`;
			dae += '<scene><instance_visual_scene url="#Scene"/></scene>';
			dae += '</COLLADA>';
			const res = {
				data: format( dae ),
				textures
			};

			if ( typeof onDone === 'function' ) {

				requestAnimationFrame( () => onDone( res ) );

			}

			return res;

		}
https://github.com/gkjohnson/collada-exporter-js

Usage:
 const exporter = new ColladaExporter();

 const data = exporter.parse(mesh);

Format Definition:
 https://www.khronos.org/collada/