npm / pnpm / yarn — comparison + when to use which

## Install dependencies
| Action | npm | pnpm | yarn |
|---|---|---|---|
| Install all | `npm install` | `pnpm install` | `yarn` |
| Add prod | `npm i pkg` | `pnpm add pkg` | `yarn add pkg` |
| Add dev | `npm i -D pkg` | `pnpm add -D pkg` | `yarn add -D pkg` |
| Add global | `npm i -g pkg` | `pnpm add -g pkg` | `yarn global add pkg` |
| Remove | `npm un pkg` | `pnpm rm pkg` | `yarn remove pkg` |
| Upgrade | `npm update pkg` | `pnpm update pkg` | `yarn upgrade pkg` |

## Run scripts
`npm run dev` / `pnpm dev` / `yarn dev`
(pnpm + yarn don't require `run` for non-reserved names.)

## Execute one-off binary (without installing)
`npx pkg arg` / `pnpm dlx pkg arg` / `yarn dlx pkg arg`

## Frozen / lockfile-strict installs (for CI)
`npm ci` (uses package-lock.json, no updates)
`pnpm install --frozen-lockfile`
`yarn install --frozen-lockfile` (yarn classic) / `yarn install --immutable` (yarn berry)

## Lockfile names
- npm → `package-lock.json`
- pnpm → `pnpm-lock.yaml`
- yarn classic → `yarn.lock`
- yarn berry → `yarn.lock` + `.yarn/cache`

## When to use which
- **pnpm**: best for monorepos + disk efficiency (content-addressable store). Fastest install. Recommended default in 2026.
- **npm**: ships with Node, no extra install. Use if you want zero ceremony.
- **yarn berry (v2+)**: best for workspaces + PnP if you want zero node_modules. Newer ecosystem support varies.

## Monorepo
- pnpm: `pnpm-workspace.yaml` + run `pnpm -F <pkg> ...`
- yarn: `workspaces` in root package.json
- npm: also supports `workspaces` since v7