那么如何处理if-else中的诺言？

只要您的函数返回承诺，就可以使用建议的第一种方法。

下面的小提琴显示了如何根据第一个解析的值采用不同的链接路径。

function myPromiseFunction() {    //Change the resolved value to take a different path    return Promise.resolve(true);}function conditionalChaining(value) {    if (value) {        //do something        return doSomething().then(doSomethingMore).then(doEvenSomethingMore);    } else {        //do something else        return doSomeOtherThing().then(doSomethingMore).then(doEvenSomethingMore);    }}function doSomething() {    console.log("Inside doSomething function");    return Promise.resolve("This message comes from doSomeThing function");}function doSomeOtherThing() {    console.log("Inside doSomeOtherthing function");    return Promise.resolve("This message comes from doSomeOtherThing function");}function doSomethingMore(message) {    console.log(message);    return Promise.resolve("Leaving doSomethingMore");}function doEvenSomethingMore(message) {    console.log("Inside doEvenSomethingMore function");    return Promise.resolve();}myPromiseFunction().then(conditionalChaining).then(function () {    console.log("All done!");}).catch (function (e) {});

您也可以只进行一个条件链接，将返回承诺分配给变量，然后继续执行应以任何一种方式运行的功能。

function conditionalChaining(value){    if (value) {        //do something        return doSomething();    } else{        //do something else        return doSomeOtherThing();    }}var promise = myPromiseFunction().then(conditionalChaining);promise.then(function(value){    //keep executing functions that should be called either way});