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js-yaml 5.3.0

npm/js-yaml/5.3.0source ↗

[5.3.0] - 2026-08-14

This release focuses on reworking the documentation and making small architectural improvements before moving forward.

Added

  • Added completely new documentation.
  • Exported DUMP_SCHEMA, the default schema used by the dumper.
  • Added YAMLException.throwAt() for throwing an error at a source position.

Changed

  • Changed flat constant exports to grouped exports: EVENT_ID, SCALAR_STYLE, COLLECTION_STYLE, and CHOMPING_MODE, along with their value types. The old exports are still preserved, but deprecated.
  • Made identify mandatory for custom tag definitions. Use identify: () => false for load-only tags.

Deprecated

  • Deprecated flat constant exports. Use grouped ones instead.

Removed

  • Removed the MERGE_KEY export (not used anymore after last fixes).

Fixed

  • Validate << sequence items at merge time, so aliased merge sources are checked too.
  • Resolve << outside of a mapping key as the plain string '<<', matching v4, instead of leaking an internal symbol into the result.