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I typed the command ionic cordova build android  and the result was that at the prompt 
Installing "ionic-plugin-keyboard" for android
Ionic-v1.cmd build Ionic-v1[3676]: c: Ws src node_contextify.cc:635: Assertion `args[1]->Isstring()' failed. 1: 00007FF7092DC6AA V8:Internal::Gcidletimehandler::Gcidletimehandler+4506 2: 00007FF7092B7416 No::Makecallback+4534 3: 00007FF7092B74CF Node:Makecallback+4719 4: 00007FF70928B7C0 No::Decodewrite+13120 5: 00007FF7097E4382 Std::vector >::_Umove+79442 6: 00007FF7097E54E9 Std::vector >::_Umove+83897 7: 00007FF7097E482C Std::vector >::_Umove+80636 8: 00007FF7097E474B Std::vector >::_Umove+80411 9: 000002EFEC85C5C1 [ERROR] An error occurred while running subprocess Ionic-v1.
    ionic-v1.cmd build exited with exit code 134.
I’m having a similar problem when trying to run the app directly on my phone
ionic cordova run android --device
Man ionic info
    Ionic:
   Ionic CLI         : 5.0.2 (C:\Users\DEV02\AppData\Roaming\npm\node_modules\ionic)
   Ionic Framework   : ionic1 1.1.0
   @ionic/v1-toolkit : 1.0.22
Cordova:
   Cordova CLI       : 9.0.0 ([email protected])
   Cordova Platforms : android 7.1.4
   Cordova Plugins   : no whitelisted plugins (11 plugins total)
Utility:
   cordova-res : not installed
   native-run  : 0.2.4
System:
   NodeJS : v10.16.0 (C:\Program Files\nodejs\node.exe)
   npm    : 6.9.0
   OS     : Windows 10
I found the answer on this link: https://github.com/ionic-team/ionic-cliissues/3462
– Lucas Vilas Boas