How is the setting important to the plot of the story?

The setting of this novel is a major part to the plot of this novel. Catcher in the Rye is set during the late 1940's to early 1950's, around the start of the war to the end of it, in New York City. This creates a very different dynamic compared to current day. The time frame is important to the plot because Holden does things that he would not be able to do if he was trying to in the present day. To start off, he leaves Pency Prep a few days before he was really supposed to leave for Christmas break. In present day, his parents would've been told instantly that he is skipping. Him being aloud to leave is because of the setting, meaning that the rest of the book wouldn't even be able to happen. 
Another reason why setting is such a large part of the novel is because he shows that he has mental health issues that we as an audience now can see. During Holden's life there is no awareness that mental health is even a thing, everyone thinks that he just crazy and cannot be helped. A lot of these problems come from when his younger brother Allie passed away. If the setting was different than Holden would of been able to get help and maybe would not have such crazy problems.