Change yarn to npm in TravisCI config

[declanvk]

No description provided.

[ddavidebor]

Why?

[declanvk]

@ddavidebor Do you have gitter? I sent a message explaining my reasoning. I'll copy it below.

Hello, I am the intern working on Jupyterlab and I’m currently encountering some issues around Travis and the use of yarn.

Specifically, any use of yarn && yarn build will produce errors similar to :

$ tsc && node ./scripts/extract.js && node ./scripts/copyassets.js && npm run build:pack
node_modules/@jupyterlab/apputils/node_modules/@types/react/index.d.ts(3757,13): error TS2403: Subsequent variable declarations must have the same type.  Variable 'a' must be of type 'DetailedHTMLProps<AnchorHTMLAttributes<HTMLAnchorElement>, HTMLAnchorElement>', but here has type 'DetailedHTMLProps<AnchorHTMLAttributes<HTMLAnchorElement>, HTMLAnchorElement>'.
node_modules/@jupyterlab/apputils/node_modules/@types/react/index.d.ts(3758,13): error TS2403: Subsequent variable declarations must have the same type.  Variable 'abbr' must be of type 'DetailedHTMLProps<HTMLAttributes<HTMLElement>, HTMLElement>', but here has type 'DetailedHTMLProps<HTMLAttributes<HTMLElement>, HTMLElement>'.
node_modules/@jupyterlab/apputils/node_modules/@types/react/index.d.ts(3759,13): error TS2403: Subsequent variable declarations must have the same type.  Variable 'address' must be of type 'DetailedHTMLProps<HTMLAttributes<HTMLElement>, HTMLElement>', but here has type 'DetailedHTMLProps<HTMLAttributes<HTMLElement>, HTMLElement>'.

I looked it up and apparently yarn does some funny business related to copying the node_modules, see yarnpkg/yarn#1334 and DefinitelyTyped/DefinitelyTyped#18484

My conclusion was I should switch TravisCI to use npm only, instead of yarn. I wanted to get your thoughts on this, and any advice you may have concerning.

[declanvk]

I was working on a fix for a different branch (#157) and I kept getting failures. I tried to reproduce the changes on my machine using npm and I was not able to. I then switched to yarn and the same errors popped up.

I apologize for all the grammar and spelling mistakes.

[declanvk]

@ddavidebor Sadly, npm did not seem to be the perfect solution to my problems.

If you have any advice, please let me know. If not I'll probably close and delete this branch.

[declanvk]

@ddavidebor Would it be possible to chat on gitter or some other platform about this?

[ddavidebor]

Yes but I do not think I am the most competent person in the matter here. I mostly followed CI and app building, I have a limited understanding of jupyterlab peculiarities regarding all the node modules behind the app. Il gio 12 apr 2018, 18:46 Declan Kelly <notifications@github.com> ha scritto:

…

@ddavidebor <https://github.com/ddavidebor> Would it be possible to chat on gitter or some other platform about this? — You are receiving this because you were mentioned. Reply to this email directly, view it on GitHub <#158 (comment)>, or mute the thread <https://github.com/notifications/unsubscribe-auth/AIot_g1uFFnXqkVTngH80HyAvVwnWF9tks5tn4THgaJpZM4TFtz1> .

[declanvk]

Closing in favour of PR #162