From 6ca7622de83d93b175c99c2b3d0dba5d371d3203 Mon Sep 17 00:00:00 2001
From: zjf 7.6 : Chaining Promises with
Notes:
then()
then()
a resolve function or provide a non-function, no error will occur. The next then()
resolve function is passed an undefined
value.then()
a resolve function or provide a non-function, no error will occur, and the next then()
resolve function will passed the value the current resolve function passed.