Loading "grunt-karma.js" tasks...ERROR >> TypeError: Cannot read property 'prototype' of undefined Warning: Task "karma:unit" not found. Use --force to continue.

[fede1984]

Loading "grunt-karma.js" tasks...ERROR

TypeError: Cannot read property 'prototype' of undefined
Warning: Task "karma:unit" not found. Use --force to continue.

How I fix this problem?
appears when I want to run grunt watch

[YodasMyDad]

I'm also getting this error

[tyagister]

same error with grunt watch.

[torgebauer]

My try: go to package.json and change the following 2 lines:
"grunt-karma": "^0.12.2",
"karma": "^1.6.0",

It worked for me.

[sakthigithub]

Actually i done the this changes
"grunt-karma": "^0.12.2",
"karma": "^1.6.0"

But still I'm facing the same issue any suggestions ?

[haephrati]

I was also getting the same error. I fixed it by calling:
npm audit fix --force

[MiguelBarcelo]

I was also getting the same error. I fixed it by calling:
npm audit fix --force

It works for me...
When I run > grunt watch
The firefox browser was opened over and over again...