'的重要性；旗帜'；Node.js的createReadStreams/createWriteStreams中的选项？

fs

模块的

ReadStream

和

WriteStream

模块的

ReadStream

和

WriteStream

的“标志”选项的意义是什么？标志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（如果文件存在）（这是默认值），而如果使用标志

r+

，它将只修改文件（如果文件存在），因为它实际打开文件进行读写，或者如果文件不存在，它将出错

以下是丢失的旗帜，并有说明：

'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.

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标志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（如果文件存在）（这是默认值），而如果使用标志

r+

，它将只修改文件（如果文件存在），因为它实际打开文件进行读写，或者如果文件不存在，它将出错

以下是丢失的旗帜，并有说明：

'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.