Switch from npm to yarn

[li-boxuan]

Now we are using npm, but facing some problems:

1. We are committing package-lock.json. If a contributor uses npm@6, there will be lots of carets before version number "^1.0.2". However, if another contributor uses npm@5, there will not be carets. See npm install changes package-lock.json from exact versions to loosly versions npm/npm#20434 (comment).

2. An issue regarding non-optional packages. See package-lock.json: Include only non-optional packages #87

[jayvdb]

My understanding is that yarn has similar, or worse, problems with optional packages.

[123vivekr]

Node Version Manager (NVM) can be used to load specific versions of npm. So everyone can work on the same version of node and avoid issues with dependency versions. What do you think about this?

[li-boxuan]

I am using nvm to switch versions. But is there a good way to force everyone to use the same version of node?

[bhawesh96]

https://nitayneeman.com/posts/standardizing-node.js-version-in-an-npm-package/

This looks a simple good hack to me