GeezerVison

Sourced from js-yaml's changelog.

[5.0.0] - 2026-06-20

Added

• Added named exports for schemas, tags, parser events and AST utilities.
• Reworked JSON_SCHEMA and CORE_SCHEMA with spec-compliant scalar resolution rules, and added YAML11_SCHEMA.
• Added realMapTag for lossless mappings with non-string and complex keys. Object-based mappings now reject complex keys instead of stringifying them.
• Added dump() transform option for changing the generated AST before rendering.
• Added dump() options seqInlineFirst, flowBracketPadding, flowSkipCommaSpace, flowSkipColonSpace, quoteFlowKeys, quoteStyle and tagBeforeAnchor.
• Added formal data layers (events and AST) for modular data pipelines.
  • Added low-level parser (to events), presenter and visitor APIs.
• Added the YAML Test Suite to the test set.

Changed

• See the migration guide for upgrade notes.
• Rewritten in TypeScript and reorganized the public API around flat named exports.
• Reduced the set of exported schemas:
  • YAML 1.2 schemas: CORE_SCHEMA (loader default), JSON_SCHEMA, FAILSAFE_SCHEMA.
  • YAML11_SCHEMA, a combination of all YAML 1.1 tags (YAML 1.1 does not specify a schema, only "types").
• load/dump default behaviour is now specified exactly via schemas:
  • load uses CORE_SCHEMA, without !!merge by default.
  • dump uses YAML11_SCHEMA + CORE_SCHEMA for the quoting check, to guarantee backward compatibility by default.
• !!set is now loaded as a JavaScript Set.
• Replaced the Type API with a tags API. Similar, but more precise and simpler. See examples for details. Tags can be defined via defineScalarTag(), defineSequenceTag() and defineMappingTag(), or as a spread + override of an existing tag.
• Renamed Schema.extend() to Schema.withTags().
• Expanded YAML 1.2 conformance and improved handling of directives, document markers, block keys, multiline scalars, tag syntax and other things.
• load() now throws on empty input instead of returning undefined.
• Moved browser builds to the js-yaml/browser export.
• Deprecated the loadAll signature with an iterator (still works, but is a candidate for removal).

Removed

• Removed deprecated safeLoad(), safeLoadAll() and safeDump() exports.
• Removed DEFAULT_SCHEMA and the nested types export.
• Removed loader options onWarning, legacy and listener.
• Removed dumper options styles, replacer, noCompatMode, condenseFlow, quotingType and forceQuotes. Renamed noArrayIndent to seqNoIndent. Formatting and representation are now configured through presenter options,

... (truncated)

• 75148bc 5.0.0 released
• 704b25d Quote document markers followed by whitespace
• 42dea28 Support complex !!pairs keys with realMapTag
• 6cf374e Fix dumping strings that collide with YAML markers
• 65b8d94 Clarify !!omap/!!pairs support
• 33e3640 Move tagname helpers to common/ and remove unused exports
• 4dd582b Cleanup export types
• 39b3792 Add types export
• 0cd01e9 docs: update for v5
• c5a61a4 Fix presenter coverage
• Additional commits viewable in compare view

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