code: private boolean executePreStepCommand(String topLevelFolder) {
          String[] command;
          if (DependencyCollector.isWindows()) {
              command = getCommand(COMPOSER_BAT);
          } else {
              command = getCommand(COMPOSER);
          }
          String commandString = String.join(Constants.WHITESPACE, command);
          File file = new File(topLevelFolder + FORWARD_SLASH + COMPOSER_JSON);
          CommandLineProcess composerInstall = null;
          if (file.exists()) {
              logger.info("Running install command : {}", commandString);
              composerInstall = new CommandLineProcess(topLevelFolder, command);
          }
          try {
              composerInstall.executeProcessWithoutOutput();
          } catch (IOException e) {
              logger.warn("Could not run {} in folder {} : {}", commandString, topLevelFolder, e.getMessage());
              return true;
          }
          return composerInstall.isErrorInProcess();
      }
docs: execute pre step command (composer install)