我如何使用.then（）使函数在javascript中接连实现

Question

I am new in javascript. I have two asynchronous functions, but I would like then implement in some sequence, because the variable in first function will be used in second one. following code will explain more specific:

function1(){
//asynchronous
//generate some variables(a,b)
}
function2(){
//asynchronous
//use a,b
}

so if I just let them implement in this way, some time a,b are not already to be used in function2 some time(some time they are), by my guess they are implemented in parallel, some time function1 completed faster.

I know .then() will return a promise which kinda make one run first, so I am wondering is there some way like:

funtion1().then(function2());

to make funtion1 implement first then function2 Any suggestion appreciated, let me know if I misunderstand something.

Answer 1

.then is a Promise function.

function function1 () {
    return new Promise((resolve) => {
        console.log('Do your stuff here');
        const a = 1;
        const b = 2;
        resolve({ a, b });
    });
}

function function2 ({ a, b }) {
    console.log('Do your stuff here', a, b);
}

function1().then(function2)
// Do your stuff here
// Do your stuff here 1 2