Catalan opening

Why is it that sometimes when u do the Catalan openining the computer analyse from Chess.com doesn't say it's a book move, but rather that its good or an an inaccuracy. I understand it's not the best opening against any defence, but still it's wired that it don't list it as a book move or say what opening it is. 

I would also appericiate if anyone have som good videoes on this opening to share as I just started to learn it.  

You must have heard that the number of the possible first ten moves in chess is humongous. ( About 1.70 x 10^29 .)

The database of book moves can't possibly include all the possible variations.

https://www.chess.com/openings/Catalan-Opening

You likely are not playing a Catalan.  An opening is not just determined by White.  Just because you play d4, c4, Nf3, g3, Bg2, and O-O in the first 6 moves does not constitute a Catalan.

1.d4 Nf6 2.c4 e6 3.g3 d5 is a Catalan

1.d4 d5 2.c4 e6 3.Nf3 Nf6 4.g3 is a Catalan

1.d4 Nf6 2.c4 g6 3.Nf3 Bg7 4.g3 d6 is NOT a Catalan.  It is a Fianchetto King's Indian

Change 4...d6 to 4...d5 and it's a fianchetto Grunfeld

1.d4 d5 2.c4 c6 3.g3 is not a Catalan, it is a weak line against the Slav

1.d4 f5 2.c4 Nf6 3.g3 is not a Catalan, it is a Dutch

1.d4 d5 2.c4 Nc6 3.g3 is not a Catalan, it is simply junk.

Tx for the reply. So whar ur saying is that the opening isn't constituted by ur moves but what the opponent do as well. It's a higly complex opening and probably I'm way of over my head trying it out. When I do other openings like the Caro Kann or Queen's Gambit it happens that it goes in to something else like the Queen pawn opening or the Slave, but 90% it is what it is. With the Catalan it's rare I get it. I thought d4,c4 and g3 was what made the opening, with Nf6 and bg2. And u could switch the order of the moves after ur likings. ore ofcours variate if your opponent do something diff.  For us hobby players we might be better off with doing some other opening.