Error build --prod

Heelo guys, im trying to build a PWA

when i run:

 ionic platform add browser
 ionic cordova build browser 

it works very well
but i want the --prod flag to make the project better…
when i try to:

 ionic cordova build browser --prod

it give this error:

i try all kind of tests … build to android too… always works without the --prod flag…
but if i include --prod it gave this error…

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