code: function findModuleFromOptions(host, options) {
      if (options.hasOwnProperty('skipImport') && options.skipImport) {
          return undefined;
      }
      if (!options.module) {
          const pathToCheck = (options.sourceDir || '') + '/' + (options.path || '')
              + (options.flat ? '' : '/' + strings_1.dasherize(options.name));
          return core_1.normalize(findModule(host, pathToCheck));
      }
      else {
          const modulePath = core_1.normalize('/' + options.sourceDir + '/' + (options.appRoot || options.path) + '/' + options.module);
          const moduleBaseName = core_1.normalize(modulePath).split('/').pop();
          if (host.exists(modulePath)) {
              return core_1.normalize(modulePath);
          }
          else if (host.exists(modulePath + '.ts')) {
              return core_1.normalize(modulePath + '.ts');
          }
          else if (host.exists(modulePath + '.module.ts')) {
              return core_1.normalize(modulePath + '.module.ts');
          }
          else if (host.exists(modulePath + '/' + moduleBaseName + '.module.ts')) {
              return core_1.normalize(modulePath + '/' + moduleBaseName + '.module.ts');
          }
          else {
              throw new Error('Specified module does not exist');
          }
      }
  }
docs: Find the module referred by a set of options passed to the schematics.