Web front-end Promise tutorial from entry to mastery

Promise video introduction

Introduction to Promises

First experience with Promise 01

First experience with Promise 02

fs read file

ajax request

Encapsulate fs reading file operation

The promisify method performs promise style conversion

Promise encapsulates AJAX requests

Introduction to object status attributes

Introduction to object result value attributes

Promise workflow

Promise API-constructor-then-catch

Promise.resolve method

Promise.reject method

Promise.all methods

Promise.race method

How to modify the state of an object

Can multiple callbacks be executed?

Issues with the order of changing status and specifying callbacks

What determines the result returned by the then method?

Chain multiple tasks

abnormal penetration

How to terminate a promise chain

Initial structure building

Resolve and regect structure construction

resolve and regect code implementation

Thtow throws exception to change state

The state of a Promise object can only be modified once

then method executes callback

Execution of asynchronous task callbacks

Specify multiple callback implementations

Synchronously modify the status then method result return

Asynchronously modify the status then method result return

then method improvement and optimization

catch method - exception penetration and value passing

resolve method encapsulation

reject method encapsulation

all method encapsulation

race method encapsulation

Asynchronous execution of then method callback

Implementation of class version

async function

await expression

Combining async and await in practice

async and await combined to send ajax request