What does `app.use(bodyParser.json())` do?

Question

For:

bodyParser.urlencoded({extended: ...})

my research shows me that if extended: true, then you can parse nested objects, or

Answer 1

URL encoding and JSON encoding both allow to convert a (nested) object to string, but the format is different. An URL encoded string is in general not a valid JSON string.

One application may use one encoding method, and another the other. As long as they don't mix the two, it will work.