js-yaml
5.5.0 · 15 Oct 2026MIT322.7M / weekRepositoryHomepagenpmAtom feed
Upgrading js-yaml from 5.3.0 to 5.4.1
2 releases in betweenevery note read
Before you upgrade
Tick each one off as you go- breaking5.4.0
- breaking5.4.0
Security
Fixes 1 advisory affecting 5.3.0
- js-yaml: maxTotalMergeKeys does not limit CPU use for empty merge sourcesmoderate · GHSA-r3ph-w7gj-g6xm
- 5.4.1
Count empty mappings in merge sequences toward
maxTotalMergeKeysto limit CPU usage, #797.
Release by release
5.4.1nothing new or fixed in the note
- new
Added the
scalarStyleRulesdumper option to customize string formatting. See Scalar styling for details. - new
Add an explicit document-end marker after keep-chomped block scalars when needed to preserve trailing newlines.
- fixed
Accept a byte order mark at the start of each document in a stream, #791.
- fixed
Produce valid flow mappings with
quoteFlowKeysandflowSkipColonSpace, including alias and property-only keys, #786. - fixed
Preserve empty scalar items when converting block sequences to flow style.
- fixed
Do not apply the 1024-character simple-key limit to flow mapping keys.
- fixed
Count Unicode code points, rather than UTF-16 code units, for the 1024-character simple-key limit.
- new
2 other lines we could not sort, mostly version bumps
- 5.4.1
Hard-limit merge sequence size to 100.
- 5.4.0
Reworked scalar style selection. This can change formatting without changing loaded values; in particular, whitespace-only strings are now double-quoted.