663

What is the practical difference between npm install and npm update? When should I use which?

Improve this question
1

6 Answers 6

Reset to default
805

The difference between npm install and npm update handling of package versions specified in package.json:

{
  "name": "my-project",
  "version": "1.0",                               // install   update
  "dependencies": {                               // ------------------
    "already-installed-versionless-module": "*",  // ignores   "1.0" -> "1.1"
    "already-installed-semver-module": "^1.4.3"   // ignores   "1.4.3" -> "1.5.2"
    "already-installed-versioned-module": "3.4.1" // ignores   ignores
    "not-yet-installed-versionless-module": "*",  // installs  installs
    "not-yet-installed-semver-module": "^4.2.1"   // installs  installs
    "not-yet-installed-versioned-module": "2.7.8" // installs  installs
  }
}

Summary: The only big difference is that an already installed module with fuzzy versioning ...

  • gets ignored by npm install
  • gets updated by npm update

Additionally: install and update by default handle devDependencies differently

  • npm install will install/update devDependencies unless --production flag is added
  • npm update will ignore devDependencies unless --dev flag is added

Why use npm install at all?

Because npm install does more when you look besides handling your dependencies in package.json. As you can see in npm install you can ...

  • manually install node-modules
  • set them as global (which puts them in the shell's PATH) using npm install -g <name>
  • install certain versions described by git tags
  • install from a git url
  • force a reinstall with --force
Improve this answer
14
  • 23
    and what about ~1.3 ?
    – Offirmo
    Commented Feb 27, 2014 at 15:35
  • 6
    what if the version is like ^5.0.9? And is it possible to make npm install --save somePackage save the * to dependencies?
    – KwiZ
    Commented Apr 7, 2015 at 12:13
  • 7
    I'd also note that scripts like postinstall run on install, but not on update.
    – Michael Marvick
    Commented Jun 23, 2016 at 3:45
  • 3
    @BoyanKushlev I think you mean minor and patch/bugfix, not major and minor. Major is 1 for all your examples.
    – jdelman
    Commented Feb 8, 2018 at 19:37
  • 3
    In what way does npm update ignore devDependencies? I don't know if that has changed since written or not, but when I run npm update on a fresh folder that has no node_modules at all, it does install those defined in the "devDependencies" section of package.json, without supplying a --dev flag.
    – Ken Lyon
    Commented Oct 29, 2018 at 19:26
111

npm install installs all modules that are listed on package.json file and their dependencies.

npm update updates all packages in the node_modules directory and their dependencies.

npm install express installs only the express module and its dependencies.

npm update express updates express module (starting with [email protected], it doesn't update its dependencies).

So updates are for when you already have the module and wish to get the new version.

Improve this answer
10
  • 7
    if you don't specify a particular version in a package.json file, npm install will get the latest version of a module. So this a kind of an update.
    – saeed
    Commented Sep 18, 2012 at 20:44
  • 18
    So what should I use, npm install or npm update? Or, in other words, I am now using npm install and it seems to do the updating as well, is there any reason why should I ever use npm update?
    – Borek Bernard
    Commented Sep 18, 2012 at 21:58
  • 4
    So update will always update to the latest version, regardless of package.json, while install will respect the version given in package.json?
    – Borek Bernard
    Commented Sep 18, 2012 at 22:44
  • 2
    update installs (or updates to) latest version of module. install installs latest version of module if its not presented otherwise keeps current version.
    – tenphi
    Commented Mar 13, 2014 at 9:34
  • 16
    @Borek npm update will update to the latest version based on your package.json, not regardless of it. If you have "express": "3.x" and you are on version 3.1.0, it will update to the latest 3.x tag. If there is a 4.x version, it will not install the latest.
    – gcochard
    Commented Apr 9, 2014 at 21:28
51

In most cases, this will install the latest version of the module published on npm.

npm install express --save

or better to upgrade module to latest version use:

npm install express@latest --save --force

--save: Package will appear in your dependencies.

More info: npm-install

Improve this answer
2
  • 12
    npm install express@latest --save --force was exactly what I wanted.
    – ThomasReggi
    Commented Feb 14, 2014 at 0:28
  • 5
    In most cases? Any other cases?
    – Dmitri Zaitsev
    Commented Apr 18, 2015 at 5:08
16

npm update: install and update with latest node modules which are in package.json

npm install: install node modules which are defined in package.json(without update)

Improve this answer
1
  • Using npm version 6.9.0 I observe the following behavior: npm update will omit a large number of dependencies in package-lock.json. To have all required packages available and package-lock.json to be correct, I always have to execute npm install right after npm update.
    – Manfred
    Commented Apr 23, 2019 at 3:24
12

Many distinctions have already been mentioned. Here is one more:

Running npm install at the top of your source directory will run various scripts: prepublish, preinstall, install, postinstall. Depending on what these scripts do, a npm install may do considerably more work than just installing dependencies.

I've just had a use case where prepublish would call make and the Makefile was designed to fetch dependencies if the package.json got updated. Calling npm install from within the Makefile would have lead to an infinite recursion, while calling npm update worked just fine, installing all dependencies so that the build could proceed even if make was called directly.

Improve this answer
1
  • 1
    One implication is that if you updated, for instance, your redis module, and other_module requires an older version of redis, npm install other_module will guarantee that other_module will use the older version. It may add other_module/node_modules/redis if necessary.
    – jlukanta
    Commented Apr 6, 2016 at 19:26
1

npm update also installs the latest version of a package regardless of the checksum saved in package-lock.json. When depending on private repos the saved checksum can break so that npm install throws a mismatch error. npm update will ignore the checksum and install the latest version specified in package.json.

The error can look something like this:

npm WARN tarball tarball data for repo@git+ssh://[email protected]/company/repo.git#b2d8280dfb292c13c614352adra910f298a2a771 (sha512-36mxm1NMCHisdfsdfsdfsdsdf3NtFvwpzpjCEZfQTXmoi04B3qVrsTs1tnsdsdfsdfZNIK8lbEGVRVKcDX5u9pY7B==) seems to be corrupted. Trying again.
npm ERR! code EINTEGRITY
Improve this answer

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service and acknowledge you have read our privacy policy.

Not the answer you're looking for? Browse other questions tagged or ask your own question.