workspaces
Working with workspacesTable of contents
Description
Workspaces is a generic term that refers to the set of features in the npm cli that provides support to managing multiple packages from your local files system from within a singular top-level, root package.
This set of features makes up for a much more streamlined workflow handling
linked packages from the local file system. Automating the linking process
as part of npm install
and avoiding manually having to use npm link
in
order to add references to packages that should be symlinked into the current
node_modules
folder.
We also refer to these packages being auto-symlinked during npm install
as a
single workspace, meaning it’s a nested package within the current local
file system that is explicitly defined in the package.json
workspaces
configuration.
Defining workspaces
Workspaces are usually defined via the workspaces
property of the
package.json
file, e.g:
{
"name": "my-workspaces-powered-project",
"workspaces": [
"workspace-a"
]
}
Given the above package.json
example living at a current working
directory .
that contains a folder named workspace-a
that itself contains
a package.json
inside it, defining a Node.js package, e.g:
.
+-- package.json
`-- workspace-a
`-- package.json
The expected result once running npm install
in this current working
directory .
is that the folder workspace-a
will get symlinked to the
node_modules
folder of the current working dir.
Below is a post npm install
example, given that same previous example
structure of files and folders:
.
+-- node_modules
| `-- workspace-a -> ../workspace-a
+-- package-lock.json
+-- package.json
`-- workspace-a
`-- package.json
Getting started with workspaces
You may automate the required steps to define a new workspace using
npm init. For example in a project that already has a
package.json
defined you can run:
npm init -w ./packages/a
This command will create the missing folders and a new package.json
file (if needed) while also making sure to properly configure the
"workspaces"
property of your root project package.json
.
Adding dependencies to a workspace
It’s possible to directly add/remove/update dependencies of your workspaces
using the workspace
config.
For example, assuming the following structure:
.
+-- package.json
`-- packages
+-- a
| `-- package.json
`-- b
`-- package.json
If you want to add a dependency named abbrev
from the registry as a
dependency of your workspace a, you may use the workspace config to tell
the npm installer that package should be added as a dependency of the provided
workspace:
npm install abbrev -w a
Note: other installing commands such as uninstall
, ci
, etc will also
respect the provided workspace
configuration.
Using workspaces
Given the specifities of how Node.js handles module resolution it’s possible to consume any defined workspace
by it’s declared package.json
name
. Continuing from the example defined
above, let’s also create a Node.js script that will require the workspace-a
example module, e.g:
// ./workspace-a/index.js
module.exports = 'a'
// ./lib/index.js
const moduleA = require('workspace-a')
console.log(moduleA) // -> a
When running it with:
node lib/index.js
This demonstrates how the nature of node_modules
resolution allows for
workspaces to enable a portable workflow for requiring each workspace
in such a way that is also easy to publish these
nested workspaces to be consumed elsewhere.
Running commands in the context of workspaces
You can use the workspace
configuration option to run commands in the context
of a configured workspace.
Following is a quick example on how to use the npm run
command in the context
of nested workspaces. For a project containing multiple workspaces, e.g:
.
+-- package.json
`-- packages
+-- a
| `-- package.json
`-- b
`-- package.json
By running a command using the workspace
option, it’s possible to run the
given command in the context of that specific workspace. e.g:
npm run test --workspace=a
This will run the test
script defined within the
./packages/a/package.json
file.
Please note that you can also specify this argument multiple times in the command-line in order to target multiple workspaces, e.g:
npm run test --workspace=a --workspace=b
It’s also possible to use the workspaces
(plural) configuration option to
enable the same behavior but running that command in the context of all
configured workspaces. e.g:
npm run test --workspaces
Will run the test
script in both ./packages/a
and ./packages/b
.
Ignoring missing scripts
It is not required for all of the workspaces to implement scripts run with the npm run
command.
By running the command with the --if-present
flag, npm will ignore workspaces missing target script.
npm run test --workspaces --if-present