Unhandled promise rejection during 'npm run patternlab serve' causing patterns not being displayed #937
Description
I am using Pattern Lab Node v3.0.0-alpha.16 on Linux (KDE neon User Edition 5.13), with Node v10.8.0, using a Node Edition.
'node -v': v10.8.0
'npm -v': 6.4.1
Expected Behavior
After 'npm run patternlab serve' patterns should be displayed
Actual Behavior
Patterns are only displayed in top menu, but after clicking them nothing happens.
Atom .html file in /source is being built correctly
Steps to Reproduce
mkdir test-patternlab
cd test-patternlab
npm init -y && npx @pattern-lab/cli -c patternlab init
Directory for Pattern Lab project: // [ENTER], empty input
Edition: edition-node
Starter kit: starterkit-mustache-demo
Y
sudo npm install
// adding required line to package.json
sudo npm run patternlab build
sudo npm run patternlab serve
=======
Output:
test-patternlab@1.0.0 patternlab /mnt/4F44EAD3553B133C/Strona017-StartUp/test-patternlab
patternlab "serve"
Pattern Lab Node v3.0.0-alpha.16
Pattern Engine mustache: good to go
Incremental builds enabled.
Found a lower common denominator pattern state: inreview on molecules-block-media. Setting reverse lineage pattern organisms-media-list from <>
[...]
Built Pattern Lab front end
⊙ patternlab → build: Yay, your Pattern Lab project was successfully built ☺
⊙ patternlab → serve: Serving your files …
Pattern Lab Node v3.0.0-alpha.16
Pattern Lab Node v3.0.0-alpha.16
Pattern Engine mustache: already loaded, skipping.
Pattern Engine mustache: already loaded, skipping.
Incremental builds enabled.
Incremental builds enabled.
Found a lower common denominator pattern state: inreview on molecules-block-media. Setting reverse lineage pattern organisms-media-list from <>
[...]
Built Pattern Lab front end
Built Pattern Lab front end
Pattern Lab is watching for changes to files under source/
Pattern Lab is watching for changes to files under source/
Pattern Lab is being served from http://127.0.0.1:3000
Pattern Lab is being served from http://127.0.0.1:3000
(node:18688) UnhandledPromiseRejectionWarning: Error: Exited with code 3
at ChildProcess.cp.once.code (/mnt/4F44EAD3553B133C/Strona017-StartUp/test-patternlab/node_modules/opn/index.js:84:13)
at Object.onceWrapper (events.js:273:13)
at ChildProcess.emit (events.js:182:13)
at maybeClose (internal/child_process.js:962:16)
at Socket.stream.socket.on (internal/child_process.js:381:11)
at Socket.emit (events.js:182:13)
at Pipe._handle.close (net.js:599:12)
(node:18688) UnhandledPromiseRejectionWarning: Unhandled promise rejection. This error originated either by throwing inside of an async function without a catch block, or by rejecting a promise which was not handled with .catch(). (rejection id: 1)
(node:18688) [DEP0018] DeprecationWarning: Unhandled promise rejections are deprecated. In the future, promise rejections that are not handled will terminate the Node.js process with a non-zero exit code.
And patternlab doesn't work properly any more...