Migrate from npm install to bun install

bun install is a Node.js compatible npm client designed to be an incredibly fast successor to npm.

We've put a lot of work into making sure that the migration path from npm install to bun install is as easy as running bun install instead of npm install.

Designed for Node.js & Bun: bun install installs a Node.js compatible node_modules folder. You can use it in place of npm install for Node.js projects without any code changes and without using Bun's runtime.
Automatically converts package-lock.json to bun's bun.lock lockfile format, preserving your existing resolved dependency versions without any manual work on your part. You can secretly use bun install in place of npm install at work without anyone noticing.
.npmrc compatible: bun install reads npm registry configuration from npm's .npmrc, so you can use the same configuration for both npm and Bun.
Hardlinks: On Windows and Linux, bun install uses hardlinks to conserve disk space and install times.

terminal

# It only takes one command to migrate
$ bun i

# To add dependencies:
$ bun i @types/bun

# To add devDependencies:
$ bun i -d @types/bun

# To remove a dependency:
$ bun rm @types/bun

Run package.json scripts faster

Run scripts from package.json, executables from node_modules/.bin (sort of like npx), and JavaScript/TypeScript files (just like node) - all from a single simple command.

NPM	Bun
`npm run <script>`	`bun <script>`
`npm exec <bin>`	`bun <bin>`
`node <file>`	`bun <file>`
`npx <package>`	`bunx <package>`

When you use bun run <executable>, it will choose the locally-installed executable

terminal

# Run a package.json script:
$ bun my-script
$ bun run my-script

# Run an executable in node_modules/.bin:
$ bun my-executable
# such as tsc, esbuild, etc.
$ bun run my-executable

# Run a JavaScript/TypeScript file:
$ bun ./index.ts

Workspaces? Yes.

bun install supports workspaces similarly to npm, with more features.

In package.json, you can set "workspaces" to an array of relative paths.

package.json

{
  "name": "my-app",
  "workspaces": ["packages/*", "apps/*"]
}

Filter scripts by workspace name

In Bun, the --filter flag accepts a glob pattern, and will run the command concurrently for all workspace packages with a name that matches the pattern, respecting dependency order.

terminal

$ bun --filter 'lib-*' my-script
# instead of:
# npm run --workspace lib-foo --workspace lib-bar my-script

Update dependencies

To update a dependency, you can use bun update <package>. This will update the dependency to the latest version that satisfies the semver range specified in package.json.

terminal

# Update a single dependency
$ bun update @types/bun

# Update all dependencies
$ bun update

# Ignore semver, update to the latest version
$ bun update @types/bun --latest

# Update a dependency to a specific version
$ bun update @types/bun@1.3.5

# Update all dependencies to the latest versions
$ bun update --latest

View outdated dependencies

To view outdated dependencies, run bun outdated. This is like npm outdated but with more compact output.

terminal

$ bun outdated

┌────────────────────────────────────────┬─────────┬────────┬────────┐
│ Package                                │ Current │ Update │ Latest │
├────────────────────────────────────────┼─────────┼────────┼────────┤
│ @types/bun (dev)                       │ 1.1.6   │ 1.1.10 │ 1.1.10 │
├────────────────────────────────────────┼─────────┼────────┼────────┤
│ @types/react (dev)                     │ 18.3.3  │ 18.3.8 │ 18.3.8 │
├────────────────────────────────────────┼─────────┼────────┼────────┤
│ @typescript-eslint/eslint-plugin (dev) │ 7.16.1  │ 7.18.0 │ 8.6.0  │
├────────────────────────────────────────┼─────────┼────────┼────────┤
│ @typescript-eslint/parser (dev)        │ 7.16.1  │ 7.18.0 │ 8.6.0  │
├────────────────────────────────────────┼─────────┼────────┼────────┤
│ @vscode/debugadapter (dev)             │ 1.66.0  │ 1.67.0 │ 1.67.0 │
├────────────────────────────────────────┼─────────┼────────┼────────┤
│ esbuild (dev)                          │ 0.21.5  │ 0.21.5 │ 0.24.0 │
├────────────────────────────────────────┼─────────┼────────┼────────┤
│ eslint (dev)                           │ 9.7.0   │ 9.11.0 │ 9.11.0 │
├────────────────────────────────────────┼─────────┼────────┼────────┤
│ mitata (dev)                           │ 0.1.11  │ 0.1.14 │ 1.0.2  │
├────────────────────────────────────────┼─────────┼────────┼────────┤
│ prettier-plugin-organize-imports (dev) │ 4.0.0   │ 4.1.0  │ 4.1.0  │
├────────────────────────────────────────┼─────────┼────────┼────────┤
│ source-map-js (dev)                    │ 1.2.0   │ 1.2.1  │ 1.2.1  │
├────────────────────────────────────────┼─────────┼────────┼────────┤
│ typescript (dev)                       │ 5.5.3   │ 5.6.2  │ 5.6.2  │
└────────────────────────────────────────┴─────────┴────────┴────────┘

To list installed packages, you can use bun pm ls. This will list all the packages that are installed in the node_modules folder using Bun's lockfile as the source of truth. You can pass the -a flag to list all installed packages, including transitive dependencies.

terminal

# List top-level installed packages:
$ bun pm ls
my-pkg node_modules (781)
├── @types/node@20.16.5
├── @types/react@18.3.8
├── @types/react-dom@18.3.0
├── eslint@8.57.1
├── eslint-config-next@14.2.8
...

terminal

# List all installed packages:
$ bun pm ls -a
my-pkg node_modules
├── @alloc/quick-lru@5.2.0
├── @isaacs/cliui@8.0.2
│   └── strip-ansi@7.1.0
│       └── ansi-regex@6.1.0
├── @jridgewell/gen-mapping@0.3.5
├── @jridgewell/resolve-uri@3.1.2
...

Create a package tarball

To create a package tarball, you can use bun pm pack. This will create a tarball of the package in the current directory.

terminal

# Create a tarball
$ bun pm pack
Total files: 46
Shasum: 2ee19b6f0c6b001358449ca0eadead703f326216
Integrity: sha512-ZV0lzWTEkGAMz[...]Gl4f8lA9sl97g==
Unpacked size: 0.41MB
Packed size: 117.50KB

Shebang

If the package references node in the #!/usr/bin/env node shebang, bun run will by default respect it and use the system's node executable. You can force it to use Bun's node by passing --bun to bun run.

When you pass --bun to bun run, we create a symlink to the locally-installed Bun executable named "node" in a temporary directory and add that to your PATH for the duration of the script's execution.

terminal

# Force using Bun's runtime instead of node
$ bun --bun my-script

# This also works:
$ bun run --bun my-script

Global installs

You can install packages globally using bun i -g <package>. This will install into a .bun/install/global/node_modules folder inside your home directory by default.

terminal

# Install a package globally
$ bun i -g eslint

# Run a globally-installed package without the `bun run` prefix
$ eslint --init

Migrate from npm install to bun install

Run package.json scripts faster

Workspaces? Yes.

Filter scripts by workspace name

Update dependencies

View outdated dependencies

List installed packages

Create a package tarball

Shebang

Global installs

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