How do you use ”～じゃんよ。” and what exactly does it mean?


At the end of sentences in casual form I know you can use ～じゃない or ～じゃん to say
"~isn't it?" similar to ～ね. And I know ～よ at the end of a sentence can be used
like "I tell you" or for emphasis, but what happens when you use ～じゃんよ at the
end of a sentence, like in the titles of Space Dandy episodes (the examples
below)? The official English episode titles all end with ", baby" so I feel
like it's a speech pattern of someone who considers themself kinda cool. E.g.

> 流れ流されて生きるじゃんよ  
>  Live with the Flow, Baby
>
> 幻の宇宙ラーメンを探すじゃんよ  
>  The Search for the Phantom Space Ramen, Baby
>
> 騙し騙される事もあるじゃんよ  
>  Occasionally Even the Deceiver Is Deceived, Baby




The titles are non-standard Japanese (they are creative sentences). I for one
think the translations are as good as it gets.

In normal contexts they are used like this:

> 受験失敗したのは自分のせいじゃんよ  
>  (Lecturing) The reason you failed was your own fault, isn't it hey?
>
> 安っぽい店で飲みたいこともあるじゃんよ  
>  (Defending) Sometimes you wanna drink in a cheap place, don't we hey?

It generally sounds confident because you are asserting the fact, which is has
a patronizing effect. I think that's why the translation adds "baby", and I
think it does reflect the tone pretty well.

