This directory contains the OSS-Fuzz fuzz targets for FormatJS. OSS-Fuzz invokes build.sh inside its base-builder-javascript image; everything here is intended to run in that container, not as part of the FormatJS Bazel/pnpm workspace.

• fuzz_icu_messageformat_parser.js — exercises @formatjs/icu-messageformat-parser's parse() across the parser flag matrix.
• fuzz_intl_messageformat.js — drives the public intl-messageformat IntlMessageFormat constructor, format(), and formatToParts() over ten locales.
• fuzz_icu_skeleton_parser.js — covers @formatjs/icu-skeleton-parser's number and date-time skeleton entry points.

• The fuzz workspace installs the published @formatjs/* and intl-messageformat packages from npm rather than building from the local Bazel sources. This keeps the OSS-Fuzz build path independent of the monorepo toolchain.
• The published packages are ESM-only. build.sh runs a targeted Babel ESM→CommonJS transform on node_modules/@formatjs/* and node_modules/intl-messageformat so Jazzer.js (which loads targets via CommonJS require) can pick them up. Other packages in node_modules are CommonJS already and are left alone.
• @jazzer.js/core is pinned to ^2. Jazzer.js 4.0.0's prebuilt native addon requires GLIBC_2.32, which the current OSS-Fuzz base images (Ubuntu 20.04, glibc 2.31) don't provide. The pin can be dropped once the base images move past glibc 2.32.

The targets are designed to run under the OSS-Fuzz toolchain rather than standalone. To reproduce a build locally, run the standard OSS-Fuzz helper against the formatjs project at google/oss-fuzz:

python3 infra/helper.py build_fuzzers formatjs
python3 infra/helper.py check_build formatjs
python3 infra/helper.py run_fuzzer formatjs fuzz_icu_messageformat_parser