I get errors when update with git pull && npm install, below the npm debug_log

0 info it worked if it ends with ok
1 verbose cli [ '/usr/bin/node', '/usr/bin/npm', 'start' ]
2 info using npm@1.4.21
3 info using node@v8.11.1
4 verbose run-script [ 'prestart', 'start', 'poststart' ]
5 info prestart magicmirror@2.6.0
6 info start magicmirror@2.6.0
7 verbose unsafe-perm in lifecycle true
8 info magicmirror@2.6.0 Failed to exec start script
9 error magicmirror@2.6.0 start: `sh run-start.sh`
9 error Exit status 127
10 error Failed at the magicmirror@2.6.0 start script.
10 error This is most likely a problem with the magicmirror package,
10 error not with npm itself.
10 error Tell the author that this fails on your system:
10 error     sh run-start.sh
10 error You can get their info via:
10 error     npm owner ls magicmirror
10 error There is likely additional logging output above.
11 error System Linux 4.14.90-v7+
12 error command "/usr/bin/node" "/usr/bin/npm" "start"
13 error cwd /home/pi/MagicMirror
14 error node -v v8.11.1
15 error npm -v 1.4.21
16 error code ELIFECYCLE
17 verbose exit [ 1, true ]

when I manually try to start via npm start it states that

> magicmirror@2.6.0 start /home/pi/MagicMirror
> sh run-start.sh

run-start.sh: 4: run-start.sh: electron: not found

so I tried to install/update electon but had no luck

npm ERR! Error: Method Not Allowed
npm ERR!     at errorResponse (/usr/share/npm/lib/cache/add-named.js:260:10)
npm ERR!     at /usr/share/npm/lib/cache/add-named.js:203:12
npm ERR!     at saved (/usr/share/npm/node_modules/npm-registry-client/lib/get.js:167:7)
npm ERR!     at FSReqWrap.oncomplete (fs.js:135:15)
npm ERR! If you need help, you may report this *entire* log,
npm ERR! including the npm and node versions, at:
npm ERR!     <http://github.com/npm/npm/issues>

npm ERR! System Linux 4.14.90-v7+
npm ERR! command "/usr/bin/node" "/usr/bin/npm" "i" "electron"
npm ERR! cwd /home/pi/MagicMirror
npm ERR! node -v v8.11.1
npm ERR! npm -v 1.4.21
npm ERR! code E405
npm ERR! 
npm ERR! Additional logging details can be found in:
npm ERR!     /home/pi/MagicMirror/npm-debug.log
npm ERR! not ok code 0

what am I missing?