使用函数的链承诺不返回所需的回调序列

1.I'm trying to chain some promises with using functions on a global promise object. The chain sequence doesn't work as I thought. The following code output 1 3 4 2. 2.I wonder what is the reason for this. My thought is in the variable declaration pass, p.then() function registered but not its following promises, not until the p.then() function returns, it start to push the second then function in callback queue.1.I'm trying to chain some promises with using