Possible problem with JSON - Ionic

[I apologize for my English, I am not speaking]
I am beginning with ionic (this is my first application) and I end up with a problem, likely related to JSON.

Normally when I compile with Ionic serve command, there the number 5 to be displayed instead of {{ totalQuestions}}. 5 being the total noombre issues lying in my JSON file. But the number 5 does not appear. There certainly is a problem.

Thanks for your help