The issue with custom tailored validation logic (reminds me of the hacks on top of jQuery back in the day :D) is that it doesn't scale as in: it will get complicated quickly, especially if your validation is complex (and mine was, that's why I had to leave Vuelidate for VeeValidate) or if you don't want to start from scratch everytime you start a new app.
I'm not saying your case should use a library, but that a library has its purposes.
Again, there's no perfect solution :D
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