static stripPublicDir(filePath, publicPath = null) {
        let publicDir = path.basename(publicPath || this.mix.config.publicPath);

        publicDir = escapeRegExp(publicDir);

        return filePath.replace(new RegExp(`^[/\\\\]?${publicDir}[/\\\\]`), '');
    }
@param {string} filePath
@param {string|null} publicPath