npm / pako

pako

What changed in pako 2 to 3, from its official release notes, upgrade guides and advisories. Sources checked 2026-11-12.

11 breaking4 new APIs and options2 performance1 tooling7 fixes and other

See which of these apply to your code, ranked, in your agent:

npx @unstale/cli init

pako 319 changes

The Uint8Array type is narrowed to ArrayBuffer only.
3.0.1release notes
Inflate no longer collects gzip headers automatically; use .onStart() with zlibInflateGetHeader() to read gzip metadata.
3.0.0release notes
The option now accepts only Uint8Array or ArrayBuffer; String is no longer accepted.
3.0.0release notes
High-level helpers use { toText: true } instead of { to: 'string' } for UTF-8 text output.
3.0.0release notes
Calling Inflate.push() after stream end returns the decode result instead of always returning false.
3.0.0release notes
The default is now false, making binary output compatible with nodejs by default.
3.0.0release notes
Now only assembles output chunks into result and no longer sets the err or msg fields.
3.0.0release notes
Package files layout changed; consult package.json for supported entry points.
3.0.0release notes
String conversion now uses native TextEncoder and TextDecoder; shims were removed.
3.0.0release notes

Exports the Z_Strategy type for compression strategy options.
3.0.3release notes
Adds hooks for advanced stream setup.
3.0.0release notes
Low-level zlib API exports are now available.
3.0.0release notes

Restores compression strategy constant exports.
3.0.3release notes
Enforces the 65536-character limit when collecting gzip header names and comments.
3.0.3release notes
Gzip header time is read as an unsigned 32-bit value, fixing negative timestamps from 2038 onward.
3.0.2release notes
Block type selection with Z_FIXED avoids fixed blocks when stored blocks would be smaller.
3.0.2release notes
A Z_STREAM_ERROR check was added for a condition reachable only through a wrong options call.
3.0.1release notes

Adds a deflate option, defaulting to true, to switch between original zlib and nodejs binary-compatible output.
2.2.0release notes

An alternate deflate hash provides nodejs zlib-compatible output and about a 40% speed boost.
2.2.0release notes

Inflate now emits a chunk on flush.
2.2.0release notes
Fixes the inflate window not being updated after inflateReset, including for multistream and bgzip.
2.2.0release notes