How does the author use foreshadowing in the novel, To All the Boys I’ve Loved Before?

Peter frequently gives Lara Jean donuts as a surprise, from which, the reader can infer that Peter is not such a bad guy after all, despite popular conceptions of him that suggest otherwise. When Peter is late to pick up Lara Jean one morning, she takes it as a sign of his arrogance before he explains that he was late because he wanted to get her a freshly baked doughnut as a surprise. On the ski trip, Peter bringing doughnuts as another surprise for Lara Jean foreshadows his announcement that he has developed feelings for her.