Promise基础教程

定义异步函数

    testOne(resolve:any, reject:any){
        setTimeout(() => {
            resolve("one");
        }, 3000);
    }
    testTwo(resolve:any, reject:any){
        setTimeout(() => {
            resolve("two");
        }, 3000);
    }
    testThree(resolve:any, reject:any){
        setTimeout(() => {
            resolve("three");
        }, 3000);
    }

定义 Promise

let result = new Promise(this.testOne)
                        .then((resultOne)=>{
                            console.log(resultOne);
                            return new Promise(this.testTwo);
                        })
                        .then((resultTwo)=>{
                            console.log(resultTwo);
                            return new Promise(this.testThree);
                        })
                        .then((resultThree)=>{
                            console.log(resultThree);
                        });
        console.log(result);