Node.js环境中同步分行读取文件

In Node.js environment, readline module supports asynchronously reading a file line by line. However, synchronously reading  is not supported.  Inspired by the codes in https://stackoverflow.com/questions/7545147/nodejs-synchronization-read-large-file-line-by-line.   Readlinesyn, a Node.js module, as shown following, provides synchronously reading functionality.In Node.js environment, readline module support