Ionic 4 not working in android 5

Ionic 4 apps won’t work in android 5.

When I opened in the browser also, it’s not loading. I could see the error

Uncaught SyntaxError: Use of const in strict mode.       vendor.js:71605

Ionic info output

Ionic:

   ionic (Ionic CLI)          : 4.1.1 (/Users/myname/.nvm/versions/node/v9.4.0/lib/node_modules/ionic)
   Ionic Framework            : @ionic/angular 4.0.0-beta.3
   @angular-devkit/core       : 0.7.4
   @angular-devkit/schematics : 0.7.4
   @angular/cli               : 6.1.5
   @ionic/ng-toolkit          : 1.0.6
   @ionic/schematics-angular  : 1.0.5

Cordova:

   cordova (Cordova CLI) : 8.0.0
   Cordova Platforms     : android 7.0.0, browser 5.0.4
   Cordova Plugins       : cordova-plugin-ionic-keyboard 2.1.2, cordova-plugin-ionic-webview 2.1.0, (and 4 other plugins)

System:

   Android SDK Tools : 26.1.1 (/Users/myname/Library/Android/sdk/)
   NodeJS            : v9.4.0 (/Users/myname/.nvm/versions/node/v9.4.0/bin/node)
   npm               : 6.4.0
   OS                : macOS High Sierra

Building an android project in Ionic is a big headache. I won’t take this much time to develop.

Ionic 4 works only with android 7 plus as of my knowledge

try to un-comment all the polyfills in polyfill.js

I tried it and that worked, thanks