code: function assertNode6PublishingPrerequisite() {
      return node.getNodeInfos().then((nodeInfos) => {
          if (nodeInfos.isAtLeastNode6 && nodeInfos.isSafeNpm) {
              return Promise.resolve();
          }
          throw new Error(
              `npm@${
                  nodeInfos.npmVersion
              } has known issues publishing when running Node.js 6. Please upgrade npm or downgrade Node and publish again. See: https://github.com/npm/npm/issues/5082`
          );
      });
  }
docs: NOTE: adopted from https://github.com/sindresorhus/np/blob/master/index.js#L78