"标志"选项在 createReadStreams/createWriteStreams of Node.js 中的重要性？

Question

当fs模块的ReadStream和WriteStream是不言自明fs.createReadStream/createWritStream时，的'标志'选项的意义是什么？

Answer 1

Flag 选项允许您设置与写入或覆盖文件相关的不同行为。

例如，在创建WriteStream时，如果传递标志w它将覆盖文件(如果存在)(这是默认值)，而如果您使用标志r+，它将只修改文件(如果它存在)，因为它实际打开文件进行读取和写入，或者如果不存在，则会出现错误。

这是丢失的旗帜和解释：

'r' - Open file for reading. An exception occurs if the file does not exist.
'r+' - Open file for reading and writing. An exception occurs if the file does not exist.
'w' - Open file for writing. The file is created (if it does not exist) or truncated (if it exists).
'w+' - Open file for reading and writing. The file is created (if it does not exist) or truncated (if it exists).
'a' - Open file for appending. The file is created if it does not exist.
'a+' - Open file for reading and appending. The file is created if it does not exist.