Promise --- synchronize? Asynchronous?

Preface ： When it comes to asynchronous programming, the first thing that comes to mind is ES6 New syntax Promise, but Promise Is it synchronous or asynchronous ？

Synchronous programming ？ Asynchronous programming ？

In judging Promise Before synchronous or asynchronous , We need to understand what synchronization is ？ What is asynchronous

Analysis of examples ：

background ： i'm hungry , I want to eat fried chicken in the North , But some people are greedy for the chicken pot in the South .

Scheme 1 ： First go north to buy fried chicken , After buying fried chicken, go to the south to buy chicken pot .

Option two ： Take out , Do both at the same time , Whoever does it first will send it first

Plan 1: buy chicken pot after you get the fried chicken , A process with a fixed sequence is called Sync

The process of scheme 2, who is the fastest and who is the first, is called asynchronous

Promise Synchronous or asynchronous ？

Promise yes ES6 The introduction of a new solution to asynchronous programming , but Promise It's synchronous

give an example ：

 let learn = new Promise((resolve, reject) => {

            console.log(' It is synchronization that I appear first ');
 });
 console.log(' It's asynchrony that I appear first ');

Print it on the console ：

analysis ：

“ It's asynchrony that I appear first ” Is faster than “ It is synchronization that I appear first ” Fast parsing speed

In case of asynchronous execution , The first output of the console should be “ It's asynchrony that I appear first ”

However, the print results are executed in sequence , Therefore, it can be judged as Synchronous execution

summary ：Promise It's synchronous