Optional attrsThe file's attributes. These are traditionally somewhat complicated and platform-dependent, so using them is scarcely necessary. However, here is a representation of what this is, bit by bit:
TTTTugtrwxrwxrwx0000000000ADVSHR
TTTT = file type (rarely useful)
u = setuid, g = setgid, t = sticky
rwx = user permissions, rwx = group permissions, rwx = other permissions
0000000000 = unused
A = archive, D = directory, V = volume label, S = system file, H = hidden, R = read-only
If you want to set the Unix permissions, for instance, just bit shift by 16, e.g. 0o644 << 16.
Note that attributes usually only work in conjunction with the os setting: you must use
os = 3 (Unix) if you want to set Unix permissions
Optional commentThe comment to attach to the file. This field is defined by PKZIP's APPNOTE.txt, section 4.4.26. The comment must be at most 65,535 bytes long UTF-8 encoded. This field is not read by consumer software.
The compression format for the data stream. This number is determined by the spec in PKZIP's APPNOTE.txt, section 4.4.5. For example, 0 = no compression, 8 = deflate, 14 = LZMA
A CRC of the original file contents. This attribute may be invalid after the file is added to the ZIP archive; it must be correct only before the stream completes.
If you don't want to have to generate this yourself, consider extending the ZipPassThrough class and overriding its process() method, or using one of ZipDeflate or AsyncZipDeflate.
Optional extraExtra metadata to add to the file. This field is defined by PKZIP's APPNOTE.txt, section 4.4.28. At most 65,535 bytes may be used in each ID. The ID must be an integer between 0 and 65,535, inclusive.
This field is incredibly rare and almost never needed except for compliance with proprietary standards and software.
The filename to associate with the data provided to this stream. If you
want a file in a subdirectory, use forward slashes as a separator (e.g.
directory/filename.ext). This will still work on Windows.
Optional flagBits 1 and 2 of the general purpose bit flag, specified in PKZIP's APPNOTE.txt, section 4.4.4. Should be between 0 and 3. This is unlikely to be necessary.
Optional mtimeWhen the file was last modified. Defaults to the current time.
Optional ondataThe handler to be called when data is added. After passing this stream to the ZIP file object, this handler will always be defined. To call it:
stream.ondata(error, chunk, final)
error = any error that occurred (null if there was no error)
chunk = a Uint8Array of the data that was added (null if there was an error)
final = boolean, whether this is the final chunk in the stream
Optional osThe operating system of origin for this file. The value is defined by PKZIP's APPNOTE.txt, section 4.4.2.2. For example, 0 (the default) is MS/DOS, 3 is Unix, 19 is macOS.
The size of the file in bytes. This attribute may be invalid after the file is added to the ZIP archive; it must be correct only before the stream completes.
If you don't want to have to compute this yourself, consider extending the ZipPassThrough class and overriding its process() method, or using one of ZipDeflate or AsyncZipDeflate.
Optional terminateA method called when the stream is no longer needed, for clean-up purposes. This will not always be called after the stream completes, so you may wish to call this.terminate() after the final chunk is processed if you have clean-up logic.
A stream that can be used to create a file in a ZIP archive