three.js/src/textures/CompressedCubeTexture.js

import { CubeReflectionMapping } from '../constants.js';
import { CompressedTexture } from './CompressedTexture.js';

class CompressedCubeTexture extends CompressedTexture {

	constructor( images, format, type ) {

		super( undefined, images[ 0 ].width, images[ 0 ].height, format, type, CubeReflectionMapping );

		this.isCompressedCubeTexture = true;
		this.isCubeTexture = true;

		this.image = images;

	}

}

export { CompressedCubeTexture };