GitHub – jbergstroem/metafile-codecov-bundle

Convert bun or esbuild
metafile output to
Codecov bundle analysis format.

Both bun and esbuild produce an identical metafile JSON format describing
the build. This package transforms that into Codecov’s v3 bundle analysis
payload and can upload it directly using GitHub Actions OIDC.

bun add -d metafile-codecov-bundle
# or
npm install -D metafile-codecov-bundle

Generate a metafile during your build, then convert it:

# bun
bun build --outdir=dist --metafile=metafile.json ./src/index.ts
metafile-codecov -f metafile.json -n my-app --bundler-name bun --bundler-version 1.2.0

# esbuild
esbuild src/index.ts --bundle --outdir=dist --metafile=metafile.json
metafile-codecov -f metafile.json -n my-app --bundler-name esbuild --bundler-version 0.24.0

The Codecov JSON is written to stdout. To write to a file instead:

metafile-codecov -f metafile.json -n my-app -o codecov-bundle-stats.json

When --output-dir is provided, gzip sizes are computed by reading the
actual output files from disk. Without it, gzipSize will be null.

import { readFileSync, writeFileSync } from "node:fs";
import { transformMetafile } from "metafile-codecov-bundle";

const metafile = JSON.parse(readFileSync("metafile.json", "utf-8"));
const payload = transformMetafile(metafile, {
	bundleName: "my-app",
	outputDir: "dist",
	bundler: { name: "bun", version: "1.2.0" },
});

writeFileSync("codecov-bundle-stats.json", JSON.stringify(payload));

Transforms a bun/esbuild metafile into a Codecov OutputPayload.

The metafile parameter accepts the Metafile type exported by this package.
It is also compatible with esbuild’s Metafile type from the esbuild package.

The --upload flag uploads bundle stats directly to Codecov using GitHub Actions
OIDC authentication. No token required — the workflow must have id-token: write
permission.

permissions:
  id-token: write

steps:
  - name: Build
    run: bun build --outdir=dist --metafile=metafile.json ./src/index.ts

  - name: Upload bundle stats
    run: bunx metafile-codecov-bundle -f metafile.json -n my-app --upload

import { fetchOidcToken, getServiceParams, uploadBundleStats } from "metafile-codecov-bundle";

const result = await uploadBundleStats({
	payload: JSON.stringify(codecovPayload),
	oidcToken: await fetchOidcToken(),
	serviceParams: getServiceParams(),
});

The metafile contains inputs (source modules) and outputs (bundled files).
These map to Codecov’s payload as follows:

Source map files (.map) are excluded. Asset filenames containing 8+ hex
character hashes are normalized (e.g., main-2c458a0c.js becomes main-*.js)
for stable cross-build comparison.

MIT