code: function setupCompressions() {
          //register all provided compressions
          if (opts.customCompressions && opts.customCompressions.length > 0) {
              for (var i = 0; i < opts.customCompressions.length; i++) {
                  var customCompression = opts.customCompressions[i];
                  registerCompression(customCompression.encodingName, customCompression.fileExtension);
              }
          }
  
          //enable brotli compression
          if (opts.enableBrotli) {
              registerCompression("br", "br");
          }
  
          //gzip compression is enabled by default
          registerCompression("gzip", "gz");
      }
docs: Reads the options into a list of available compressions.