signal-client module not found

Did a fresh checkout, ran npm install (which succeeded) and then I still get a module not found exception:

feedc0de@somewhere:/opt/matrix-puppet-signal$ npm install signal-client
npm WARN matrix-puppet-signal@1.1.0 No repository field.

+ signal-client@1.0.6
updated 2 packages in 27.596s
feedc0de@scw-admiring-ishizaka:/opt/matrix-puppet-signal$ npm run link

> matrix-puppet-signal@1.1.0 link /opt/matrix-puppet-signal
> node -e "new (require('signal-client'))('matrix').link()"

internal/modules/cjs/loader.js:797
    throw err;
    ^

Error: Cannot find module '/opt/matrix-puppet-signal/node_modules/signal-desktop/components/long/dist/Long'
Require stack:
- /opt/matrix-puppet-signal/node_modules/signal-client/index.js
- /opt/matrix-puppet-signal/[eval]
    at Function.Module._resolveFilename (internal/modules/cjs/loader.js:794:15)
    at Function.Module._load (internal/modules/cjs/loader.js:687:27)
    at Module.require (internal/modules/cjs/loader.js:849:19)
    at require (internal/modules/cjs/helpers.js:74:18)
    at signalRequire (/opt/matrix-puppet-signal/node_modules/signal-client/index.js:14:35)
    at Object.<anonymous> (/opt/matrix-puppet-signal/node_modules/signal-client/index.js:78:16)
    at Module._compile (internal/modules/cjs/loader.js:956:30)
    at Object.Module._extensions..js (internal/modules/cjs/loader.js:973:10)
    at Module.load (internal/modules/cjs/loader.js:812:32)
    at Function.Module._load (internal/modules/cjs/loader.js:724:14)
    at Module.require (internal/modules/cjs/loader.js:849:19)
    at require (internal/modules/cjs/helpers.js:74:18)
    at [eval]:1:6
    at Script.runInThisContext (vm.js:116:20)
    at Object.runInThisContext (vm.js:306:38)
    at Object.<anonymous> ([eval]-wrapper:9:26) {
  code: 'MODULE_NOT_FOUND',
  requireStack: [
    '/opt/matrix-puppet-signal/node_modules/signal-client/index.js',
    '/opt/matrix-puppet-signal/[eval]'
  ]
}
npm ERR! code ELIFECYCLE
npm ERR! errno 1
npm ERR! matrix-puppet-signal@1.1.0 link: `node -e "new (require('signal-client'))('matrix').link()"`
npm ERR! Exit status 1
npm ERR! 
npm ERR! Failed at the matrix-puppet-signal@1.1.0 link script.
npm ERR! This is probably not a problem with npm. There is likely additional logging output above.

npm ERR! A complete log of this run can be found in:
npm ERR!     /home/feedc0de/.npm/_logs/2019-10-23T15_54_23_299Z-debug.log

I'm using an arch installation which is up-to-date, nodejs and npm provided by the repositories.

matrix-hacks / matrix-puppet-signal

signal-client module not found #27