Optionalchecktrue to throw an ERR_AMBIGUOUS_ARCHIVE error when calling FileEntry#getData if the local
file header of the entry disagrees with its central directory record in a way that could make other tools
(e.g. streaming readers based on local file headers) interpret the entry differently. This detects mismatched
filenames, general purpose bit flags (encryption, data descriptor and language encoding flags), compression
methods, CRC-32 checksums and sizes. The extra fields are not compared because the zip specification allows
them to differ.
This is the boolean form of ZipReaderOptions#strictness: true means "strict" and false means
any value but "strict". When both options are set, the value passed to FileEntry#getData takes
precedence over the value passed to the constructor of ZipReader, and strictness takes precedence
over checkAmbiguity when both are set at the same level. false downgrades an inherited "strict" value
to "balanced" and leaves an inherited "tolerant" value unchanged.
Optionalchecktrue to verify the authentication code of entries encrypted with AES. The verification detects encrypted
data tampered or corrupted after the encryption.
Optionalchecktrue to verify the CRC-32 checksum of the entry against the value stored in the zip file. The verification
is run on the decompressed data and covers the whole read pipeline. It also applies to entries encrypted with
AES in AE-1 format. It is skipped for entries in AE-2 format because they store a zeroed CRC-32 value.
Optionalchecktrue to reject the entry with an ERR_AMBIGUOUS_ARCHIVE error when its local file header
disagrees with its central directory record while calling FileEntry#getData, false to deposit
the differences on EntryMetaData#warnings instead. This is the entry-level half of
ZipReaderOptions#checkAmbiguity, exposed on its own so it can be enabled without the archive-level
checks and disabled without giving up the rest of ZipReaderOptions#strictness. It is the only way to
validate the local file headers of a self-extracting archive, since
GetEntriesOptions#checkAmbiguity rejects prepended data outright.
true compares the filename as well, like ZipReaderOptions#strictness set to "strict"; false
compares everything except the filename, like "tolerant". Set
ZipReaderOptions#checkLocalFilename to control the filename comparison on its own. An explicit
value takes precedence over the strictness default at every level.
true when ZipReaderOptions#strictness is "strict" or "balanced", false when
it is "tolerant".
Optionalchecktrue to compare the filename of the local file header with the one of the central directory record when
calling FileEntry#getData, false to leave the filename out of that comparison.
Comparing the filename costs one extra read per entry whenever the local file header carries no extra
field, which is why it is left out below ZipReaderOptions#strictness set to "strict". This option
selects what is compared without changing whether a difference throws or warns, which
ZipReaderOptions#checkLocalDirectory decides. It is therefore the only way to obtain
WARNING_MISMATCHED_LOCAL_FILE_HEADER_FILENAME as a warning, with
{ checkLocalFilename: true, checkLocalDirectory: false }, and the only way to keep every other check of
"strict" without paying the extra read, with { checkLocalFilename: false, strictness: "strict" }.
the value of ZipReaderOptions#checkLocalDirectory when it is set, otherwise true
when ZipReaderOptions#strictness is "strict" and false when it is "balanced" or
"tolerant".
Optionalchecktrue to throw an ERR_OVERLAPPING_ENTRY error when calling FileEntry#getData if the entry
overlaps with another entry on which FileEntry#getData has already been called (with the option
checkOverlappingEntry or checkOverlappingEntryOnly set to true).
Optionalchecktrue to throw an ERR_OVERLAPPING_ENTRY error when calling FileEntry#getData if the entry
overlaps with another entry on which FileEntry#getData has already been called (with the option
checkOverlappingEntry or checkOverlappingEntryOnly set to true) without trying to read the content of the
entry.
Optionalchecktrue to check only if the password is valid.
Optionalchecktrue to check the CRC-32 checksum of the entry.
Use ZipReaderOptions#checkCrc32 instead.
Optionalconcurrenttrue to write independent files concurrently instead of one after another.
When an entry fails, the entries still in flight are cancelled and the ones not started yet are
skipped, so a failed export stops as early as it does when writing one file after another. An
entry whose write has already been requested may still be created, because the File System
Access API cannot cancel a pending getFileHandle or getDirectoryHandle call.
Optionalpasstrue to read the data as-is without decompressing it and without decrypting it, "compressed" to decrypt
it without decompressing it.
The codecs run in a fixed order, the data is decrypted and then decompressed, so this option selects how
many of these two stages are skipped rather than which one. "compressed" therefore returns the data of the
entry still compressed but no longer encrypted, and it is the only way to obtain it: the value true returns
the stored bytes, which are still encrypted, and an unset value returns the content itself. Reading an entry
which is not encrypted gives the same result with true and with "compressed".
Since the encryption is undone, "compressed" needs the ZipReaderOptions#password option and
throws an ERR_INVALID_PASSWORD error when it is wrong, whereas true never looks at the password.
The ZipReaderOptions#checkAuthenticationCode option applies as well. The
ZipReaderOptions#checkCrc32 option does not, since the CRC32 of the entry describes its
content and the content is not decompressed.
Two entries holding the same content encrypted with two different passwords have no bytes in common when
they are read with true, because the salt is drawn per entry. Read with "compressed" they are identical,
which is what makes it possible to compare the content of encrypted entries without decompressing them.
A value which is neither a boolean, "compressed" nor unset throws an ERR_INVALID_PASS_THROUGH_VALUE
error. The filesystem API copies entries verbatim and only accepts a boolean, see
ERR_UNSUPPORTED_PASS_THROUGH_VALUE.
OptionalpasswordThe password used to decrypt the content of the entry.
OptionalpasswordsThe passwords tried in order, after the ZipReaderOptions#password option and the passwords already accepted by another entry of the same imported zip file. An empty string is ignored.
When every candidate fails, the entry raises an ERR_INVALID_PASSWORD error whose cause is
the error raised by the last candidate, unless the PasswordCandidatesOptions#requestPassword
option is set.
A value which is neither an array of strings nor unset throws an ERR_INVALID_PASSWORDS error.
Optionalpreventtrue to prevent closing of WritableWriter#writable when calling FileEntry#getData.
It only applies to the writable owned by the caller. It is ignored by the Writer instances returning the written data, such as BlobWriter or TextWriter, whose writable is created internally and must be closed for Writer#getData to resolve.
OptionalrawThe password used to encrypt the content of the entry (raw).
OptionalreaderThe options passed to the Reader instances.
These options override the ones passed at the top level. The ZipReaderOptions#password option can be set here or at the top level, unlike ZipDirectoryEntryExportOptions where the top-level password encrypts the exported zip file instead.
A value which is neither an object nor unset throws an ERR_INVALID_READER_OPTIONS error.
OptionalsignalThe AbortSignal instance used to cancel the decompression.
A signal already aborted when the operation starts rejects it with ERR_ABORTED as the
reason of the AbortError, or with signal.reason when it is set, without relying on the
signal option of pipeTo that the oldest supported engines ignore. A signal aborted while the
entry is being read rejects the operation as well, whether its compressed data is still being
consumed or its content still being written; on those engines, the content is written to the end
before the operation is rejected.
OptionalstrictnessHow tolerant the reader should be when the local file header of an entry disagrees with its central directory record.
"strict": compare the filename, the general purpose bit flag, the compression method, the CRC-32
checksum and the sizes, and throw an ERR_AMBIGUOUS_ARCHIVE error on any difference."balanced": compare everything except the filename, and throw on any difference."tolerant": compare everything except the filename, and deposit the differences on
EntryMetaData#warnings instead of throwing.Every field except the filename is read from the local file header anyway, to locate the entry data, so
the comparison "balanced" performs reads no additional bytes. Comparing the filename reads the filename
bytes as well, which costs one extra read per entry whenever the local file header carries no extra field
— the common case in practice, and the reason the filename is left out below "strict". Use
ZipReaderOptions#checkLocalDirectory to request or suppress the whole comparison explicitly, and
ZipReaderOptions#checkLocalFilename to include or exclude the filename on its own.
Optionaltransfertrue to transfer stream ownership to web workers.
Optionalusetrue to use the native API CompressionStream/DecompressionStream to compress/decompress data.
When compressing, the native API is only used when level is undefined or equal to 6, see ZipWriterConstructorOptions#level.
Optionalusetrue to use web workers to compress/decompress data in non-blocking background processes.
OptionalonendThe function called when ending compression/decompression.
The total number of bytes (computed).
An empty promise or undefined.
OptionalonprogressThe function called during compression/decompression.
The current progress in bytes.
The total number of bytes.
An empty promise or undefined.
OptionalonstartThe function called when starting compression/decompression.
The total number of bytes.
An empty promise or undefined.
OptionalrequestThe function asked for a password when every candidate has failed, or when there is none. It is
called with the entry being read and with the error raised by the last candidate, which is
undefined when no candidate was tried, and it can return a promise, e.g. when it prompts the user.
A string is tried on the entry, and the function is called again when it fails, with the
ERR_INVALID_PASSWORD error. undefined or null gives up: the entry raises an
ERR_INVALID_PASSWORD error whose cause is the error raised by the last candidate, or an
ERR_ENCRYPTED error when no candidate was tried. A value of another type throws an
ERR_INVALID_REQUEST_PASSWORD error. The
function is not called for the entries whose password is already known.
When several entries are read concurrently, e.g. by {@link ZipDirectoryEntry}#export*() with the
ZipWriterConstructorOptions#bufferedWrite option, only one call is pending at a time: the
other entries wait for its answer and try it before asking themselves. Cancelling the whole
operation from the function is done with the ZipReaderOptions#signal option, since giving
up fails the entry being read only.
A value which is neither a function nor unset throws an ERR_INVALID_REQUEST_PASSWORD error.
The entry being read.
Optionalerror: Error
The error raised by the last candidate, undefined when no candidate was tried.
The password to try, or undefined to give up.
Represents the options passed to ZipDirectoryEntry#exportFileSystemHandle and ZipFS#exportFileSystemHandle.
Remarks
The ZipReaderOptions#preventClose option is ignored: the export owns the writable of each file it creates and must close it for the data to be written.