async - await

Understand:

     async/await is an ES7 proposal based on Promise's final solution to asynchrony.

Where async is a modifier added before the function, the function defined by async will return the value of a Promise object resolve by default.Therefore, the async function can be directly then, and the return value is the function passed in by the then method.

     await is also a modifier that can only be placed in functions defined by async.Can be understood as waiting.

     await If it is a Promise object modified: You can get the content returned in the Promise (the parameters of resolve or reject), and the statement will be executed after the value is obtained;

If it is not a Promise object: treat this non-promise as the result of an await expression.

How to use async/awiait Code:  

click