Following is the syntax of the method to open a file in asynchronous mode:
fs.open(PATH, flags[, mode], CALLBACK)
Parameters
Here is the description of the parameters used:
path - This is string having file name including path.
flags - Flag tells the behavior of the file to be opened. All possible values have been mentioned below.
mode - This sets the file mode (permission and sticky bits), but only if the file was created. It DEFAULTS to 0666, readable and writeable.
callback - This is the callback function which GETS two ARGUMENTS (err, fd).

Following is the syntax of the method to open a file in asynchronous mode:
fs.open(path, flags[, mode], callback)
Parameters
Here is the description of the parameters used:
path - This is string having file name including path.
flags - Flag tells the behavior of the file to be opened. All possible values have been mentioned below.
mode - This sets the file mode (permission and sticky bits), but only if the file was created. It defaults to 0666, readable and writeable.
callback - This is the callback function which gets two arguments (err, fd).