Yarn + Lerna to pnpm

OHIF 3.13 replaces the yarn + lerna toolchain with pnpm workspaces. The repository now uses a single pnpm-lock.yaml and a pnpm-workspace.yaml manifest at the root. yarn.lock, lerna.json, nx.json, bun.lock, the addOns/ directory, and preinstall.js have all been removed.

Required tools

Tool	Old minimum	New minimum
node	>=18	>=24
pnpm	(unused)	>=11
yarn	>=1.20.0	(removed)
npm	>=6	(removed)

The root package.json declares "packageManager": "pnpm@11.1.1". If you use Corepack, running any pnpm command in the repo will pick the correct version automatically:

corepack enable
corepack prepare pnpm@11.1.1 --activate

Install and run commands

Replace your existing yarn and lerna commands with their pnpm equivalents.

3.12 (yarn / lerna)	3.13 (pnpm)
yarn install --frozen-lockfile	pnpm install --frozen-lockfile
yarn install	pnpm install
yarn run dev	pnpm run dev
yarn run build	pnpm run build
yarn run test:unit	pnpm run test:unit
lerna run build --stream	pnpm -r run build
lerna run dev:viewer --stream	pnpm --filter @ohif/app run dev:viewer
lerna run clean --stream	pnpm -r run clean

The root scripts section was rewritten to use pnpm --filter @ohif/app run … for app-targeted scripts and pnpm -r run … for monorepo-wide scripts. There is no preinstall script anymore.

.npmrc

A new .npmrc at the repository root controls install behavior:

frozen-lockfile=true

CI installs error out if the lockfile would change. To update the lockfile locally, use pnpm install --no-frozen-lockfile (also exposed as the install:update-lockfile script).

pnpm-workspace.yaml

Workspace membership moved out of package.json into a dedicated file:

packages:
  - platform/*
  - extensions/*
  - modes/*
shamefullyHoist: true
allowBuilds:
  '@scarf/scarf': true
  '@swc/core': true
  core-js: true
  core-js-pure: true
  cypress: true
  protobufjs: true
  sharp: true
overrides:
  # pinned versions previously declared in package.json resolutions …

Two settings worth highlighting:

• shamefullyHoist: true keeps the install layout flat, the way yarn v1 produced it. This is required because some OHIF dependencies expect to resolve transitive packages directly from node_modules.
• allowBuilds is pnpm's allow-list for packages whose install scripts are allowed to run. If you add a dependency that ships a postinstall script (native bindings, optimized binaries, etc.) you must add it here or pnpm will skip the build.

The addOns/externals/* workspace entry from 3.12 is removed. The dicom-microscopy-viewer and externals devDependencies are now installed directly through pnpm-workspace.yaml overrides — no separate add-on install step is needed.

Workspace dependency syntax

Intra-workspace dependencies now use the workspace:* protocol instead of hard-pinned version strings:

  "dependencies": {
-   "@ohif/core": "3.13.0-beta.72",
-   "@ohif/extension-cornerstone": "3.13.0-beta.72",
-   "@ohif/ui-next": "3.13.0-beta.72"
+   "@ohif/core": "workspace:*",
+   "@ohif/extension-cornerstone": "workspace:*",
+   "@ohif/ui-next": "workspace:*"
  }

When pnpm publishes a workspace package, workspace:* is rewritten to the actual version on disk, so downstream consumers continue to see normal semver ranges in published package.json files.

If you keep an OHIF fork with extra extensions in extensions/, you do not need to add them to pnpm-workspace.yaml — the glob pattern already covers them. Inside your extension's package.json, change any @ohif/* deps from hard versions to workspace:*.

CLI changes

platform/cli (@ohif/cli) no longer wraps yarn:

• getYarnInfo and uninstallNPMPackage now shell out via execa to npm / pnpm directly rather than depending on the deprecated yarn-programmatic package.
• The CLI invokes scripts with pnpm run … and instructs new extension authors to use pnpm.
• The yarn dependency was removed from platform/cli/package.json.

If you previously ran extension/mode commands as yarn run cli …, switch to pnpm run cli ….

CLI extension and mode templates

The extension and mode templates in platform/cli/templates/*/dependencies.json were updated:

  "engines": {
-   "node": ">=14",
-   "npm": ">=6",
-   "yarn": ">=1.18.0"
+   "node": ">=24",
+   "pnpm": "11.1.1"
  },
  "scripts": {
    "dev": "cross-env NODE_ENV=development webpack --config .webpack/webpack.dev.js --watch --output-pathinfo",
-   "dev:my-extension": "yarn run dev",
+   "dev:my-extension": "pnpm rundev",
    "build": "cross-env NODE_ENV=production webpack --config .webpack/webpack.prod.js",
-   "build:package": "yarn run build",
-   "start": "yarn run dev"
+   "build:package": "pnpm runbuild",
+   "start": "pnpm rundev"
  }

Heads up: the template's pnpm rundev / pnpm runbuild strings are missing the space between run and the script name. If you generate a new extension from the CLI, replace those with pnpm run dev and pnpm run build.

Audit and lockfile maintenance

• yarn audit and the bun audit ignore list have been replaced with a plain pnpm audit in the root script.
• yarn dlx-style ad-hoc commands should use pnpm dlx instead.
• Update CI cache keys: cache ~/.local/share/pnpm/store (or the path reported by pnpm store path) keyed on pnpm-lock.yaml. Yarn cache paths are no longer populated.

Quick migration checklist

1. Install Node 24 and pnpm 11 (or use Corepack).
2. Delete node_modules and any yarn.lock/addOns/yarn.lock from your fork.
3. Replace hard-pinned @ohif/* deps with workspace:* in your workspace packages.
4. Update CI scripts to call pnpm install --frozen-lockfile and pnpm run ….
5. Update your cache key to pnpm-lock.yaml.
6. Regenerate any extensions you created from the CLI templates and fix the pnpm rundev / pnpm runbuild script names.