# What changed in prettier-plugin-hermes-parser

> 10 changes in prettier-plugin-hermes-parser 0.33 to 0.37 from its official release notes, upgrade guides and advisories: 1 new APIs and options. Each one cited. Sources checked 2026-11-15. HTML: https://unstale.sh/npm/prettier-plugin-hermes-parser/

To see which of these apply to a repository, run `npx @unstale/cli init` in it.

## prettier-plugin-hermes-parser 0.37

### Fixes and other changes

- Compatibility with Prettier 3.7+ is fixed. (0.37.0) — [release notes](https://github.com/facebook/hermes/blob/c46fa0ff98b83b27cecd321734d52c4f637854d9/tools/hermes-parser/js/prettier-plugin-hermes-parser/CHANGELOG.md#0370)

## prettier-plugin-hermes-parser 0.36

### Behavior and default changes

- Formatting now supports async component declarations. (0.36.1) — [release notes](https://github.com/facebook/hermes/blob/c46fa0ff98b83b27cecd321734d52c4f637854d9/tools/hermes-parser/js/prettier-plugin-hermes-parser/CHANGELOG.md#0361)
- Formatting now supports async hook declarations. (0.36.1) — [release notes](https://github.com/facebook/hermes/blob/c46fa0ff98b83b27cecd321734d52c4f637854d9/tools/hermes-parser/js/prettier-plugin-hermes-parser/CHANGELOG.md#0361)
- The parser now supports new Flow variance syntax. (0.36.0) — [release notes](https://github.com/facebook/hermes/blob/c46fa0ff98b83b27cecd321734d52c4f637854d9/tools/hermes-parser/js/prettier-plugin-hermes-parser/CHANGELOG.md#0360)

### Fixes and other changes

- The parser now supports the declarations array for DeclareVariable declarations. (0.36.0) — [release notes](https://github.com/facebook/hermes/blob/c46fa0ff98b83b27cecd321734d52c4f637854d9/tools/hermes-parser/js/prettier-plugin-hermes-parser/CHANGELOG.md#0360)

## prettier-plugin-hermes-parser 0.35

### Tooling

- Supports readonly as a Flow variance annotation, equivalent to + (covariant/read-only). (0.35.0) — [release notes](https://github.com/facebook/hermes/blob/c46fa0ff98b83b27cecd321734d52c4f637854d9/tools/hermes-parser/js/prettier-plugin-hermes-parser/CHANGELOG.md#0350)

## prettier-plugin-hermes-parser 0.34

### New APIs and options

- Adds support for Flow’s keyof operator, which replaces $Keys. (0.34.0) — [release notes](https://github.com/facebook/hermes/blob/c46fa0ff98b83b27cecd321734d52c4f637854d9/tools/hermes-parser/js/prettier-plugin-hermes-parser/CHANGELOG.md#0340)

### Fixes and other changes

- Fixed accidental whitespace removal by the autoformatter that caused Prettier to add unnecessary new lines. (0.34.1) — [release notes](https://github.com/facebook/hermes/blob/c46fa0ff98b83b27cecd321734d52c4f637854d9/tools/hermes-parser/js/prettier-plugin-hermes-parser/CHANGELOG.md#0341)

## prettier-plugin-hermes-parser 0.33

### Behavior and default changes

- The parser now supports Flow match instance patterns. (0.33.1) — [release notes](https://github.com/facebook/hermes/blob/c46fa0ff98b83b27cecd321734d52c4f637854d9/tools/hermes-parser/js/prettier-plugin-hermes-parser/CHANGELOG.md#0331)
- The parser now supports Flow Records. (0.33.1) — [release notes](https://github.com/facebook/hermes/blob/c46fa0ff98b83b27cecd321734d52c4f637854d9/tools/hermes-parser/js/prettier-plugin-hermes-parser/CHANGELOG.md#0331)