Use Yarn to manage dependencies

[joaomoreno]

cc @felixfbecker

We moved to Yarn to manage our dependencies. The big advantage is, of course, speed. I report 3x faster install times on my macOS machine. There are other consequences such as locking down our dev dependencies (which sometimes bite us: #37698, et al).

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For everyone in @Microsoft/vscode, please read:

What do I have to do?

1. Update Node to the latest stable version (currently: 8.9.1).
2. Install Yarn globally: npm i -g yarn
3. Clean up your vscode repo: git clean -xfd
4. Install all dependencies: yarn. You can now have a very short espresso ☕️ while you wait Compare that to the tall venti moccachino soy latte from the good old npm 4 times. Too many calories.

You're good to go.

FAQ

How do I do ./scripts/npm.sh install now?

Just:

yarn

Pretty cool, amirite?

I've also adapted scripts/npm.{sh,bat} to simply invoke yarn for the sanity of your own muscle memory.

What about npm run TASK?

You can still do that. No problem.

How can I add or update a dependency?

Both installing and updating dependencies are the same command:

yarn add [--dev] dependency[@version]

Example:

yarn add semver@4.3.6

As always, carefully review the changes made to package.json and (now) yarn.lock files before blindly committing them when adding or updating dependencies.

What are yarn.lock files?

They replace our shrinkwrap files and represent a snapshot of the dependencies to install when installing... dependencies. You don't touch them. Only Yarn touches them.

Can I manually edit dependencies in package.json or yarn.lock?

No, since those files should only be managed by Yarn itself.

On Windows, yarn fails with EBUSY errors

Yarn tries to parallelise native module compilation in order to be faster. node-gyp doesn't like this on Windows. You can set CHILD_CONCURRENCY to 1 in your user's environment to fix this.

Why not NPM5?

Basically because of npm/npm#17722

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As always, please be alert to any runtime errors, missing dependencies, strangeness; and let me know asap.

[joaomoreno]

@bpasero @Tyriar FYI the electronVersion flag is gone from package.json. You gotta edit the .yarnrc file now, when updating Electron: https://github.com/Microsoft/vscode/blob/master/.yarnrc#L2

[octref]

One tip I found useful: yarn <command> will fallback to yarn run <command> if the first command is not a top level one. This makes it really easy for me to run npm scripts. I run yarn compile all the time.

[Stanzilla]

yarn config set child-concurrency 1 to set the option.

[favna]

Concerning this line:

Install Yarn globally: npm i -g yarn

Yarn themselves recommend installing Yarn through other means than the node package manager for Linux and MacOS with the former varying on the distro and the latter having options for both Homebrew and MacPorts. Installing Yarn through npm i -g yarn on those non-Windows operating systems will have Yarn spurt out a warning recommending users to install Yarn through the for-their-operating-system recommend method (last I checked) on every command you fire up with it.

I therefore strongly suggest referencing the Yarn installation page for readers that are not using Windows: https://yarnpkg.com/lang/en/docs/install/

[felixfbecker]

@favna is there any reason why it should be done that way?

[favna]

@felixfbecker I have too little experience with the aforementioned non-Windows environments to be able to properly answer that, therefore I can only assume that if there wasn't a compelling reason to do so then Yarn wouldn't be recommending its users to install it through their recommend ways.

[felixfbecker]

@favna I could see how they don't want to be "coupled" in any way to npm, i.e. no want to require npm to install yarn, as they are a competitor to npm. It always felt weird using npm to install bower. That is definitely not a reason to "strongly suggest" stop using npm...

[Stanzilla]

As long as there is no functioning way to self-update Yarn, people will always prefer the npm method, imo.

[MonsieurMan]

@joaomoreno, you should edit this part like so as @octref mentionned :

What about npm run TASK?

You can still do that. No problem.
Or run yarn <task> if the taskname is not conflicting with any native yarn command.
It'll save time to everybody 😄

[t-sauer]

@felixfbecker you can find their reasons under „Install with npm“ under the alternatives tab on the installation docs