Interface ZipReaderConstructorOptions

true 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.

true to verify the authentication code of entries encrypted with AES. The verification detects encrypted data tampered or corrupted after the encryption.

true 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.

true 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 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" }.

true 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).

true 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.

true to check only if the password is valid.

true to check the CRC-32 checksum of the entry.

The encoding of the comment of the entry.

The option is ignored when the general purpose bit 11 is set in the header of the entry, and valid UTF-8 is detected when the option is not set, see GetEntriesOptions#filenameEncoding.

The encoding of the filename of the entry.

The option is ignored when the general purpose bit 11 is set in the header of the entry: such a filename is always decoded as UTF-8. It is only read when the bit is not set. When the option is not set either, a filename holding bytes outside ASCII is decoded as UTF-8 if they form valid UTF-8, since many writers store UTF-8 without setting the bit (macOS Archive Utility, ditto, the macOS build of Info-ZIP zip, Java 6), and as IBM Code Page 437 otherwise. Set the option to decode such filenames as another legacy encoding instead.

How strictly the filename of each entry should be validated. A rejected name throws an ERR_UNSAFE_FILENAME error carrying the offending name in its filename property.

• "strict": reject the names rejected by "balanced", plus the names that do not map cleanly to a file path, i.e. empty names, names containing a "." path component or an empty one (e.g. "a//b.txt"), and names containing a NUL character.
• "balanced": reject names that would escape the directory they are extracted into, i.e. names containing a ".." path component delimited by slashes or by backslashes (e.g. "..\\file.txt", which a Windows host resolves as a parent directory), and absolute names, i.e. names starting with "/", with a drive letter (e.g. "C:/file.txt") or with a backslash (root-relative and UNC paths on Windows).
• "tolerant": never reject a name.

A backslash is otherwise not interpreted as a path separator: it is a valid filename character on UNIX systems, and it also occurs as the trail byte of legitimate double-byte filenames (e.g. CP932) decoded with another charset.

Names are validated, never rewritten, so the filename reported for an entry always matches its central directory record.

The maximum number of bytes tolerated after the zip structure before the archive is rejected. Defaults to 0 when GetEntriesOptions#strictness is "strict", 65535 when it is "balanced", and Infinity when it is "tolerant".

An explicit value takes precedence over the strictness default at every level, so it can loosen "strict" or reintroduce a rejection under "tolerant". It also bounds how far back the end of central directory record is searched for, so a value smaller than the amount of data actually appended surfaces an ERR_EOCDR_NOT_FOUND error when the record lies beyond the searched region and an ERR_AMBIGUOUS_ARCHIVE error otherwise.

true to read the data as-is without decompressing it and without decrypting it, "compressed" to decrypt it without decompressing it.

The password used to decrypt the content of the entry.

true to prevent closing of WritableWriter#writable when calling FileEntry#getData.

The password used to encrypt the content of the entry (raw).

The 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.

How 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.

true to transfer stream ownership to web workers.

true 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.

true to use web workers to compress/decompress data in non-blocking background processes.