httpClient函數(shù)還是被調(diào)用有沒有指定return，就是默認(rèn)返回undefinded
而你需要做的就是:
傳入一個回調(diào)函數(shù)給httpClient

function httpClient(callback){

    new Promise(function(resovle,reject){
        //模擬異步執(zhí)行
        setTimeout(function(){
            resovle("DONE~~~~~");
            //reject(new Error("failed"));
        },1000);
    }).then(function(resultData){
        console.log("++++")
        callback&&callback.apply(null,[null,resultData]);
    }).catch(function(error){
        callback&&callback.apply(null,[error]);
    });
}


function runHttpClient(){
    new Promise(function(resovle,reject){
        httpClient(function(error,data){
            if(error){
                reject(error);
                return;
            }
            resovle(data);
        });
    }).then(function(result){
        console.log(">>>"+result);
    }).catch(function(error){
        console.err(error);
    });
}

runHttpClient();

或者讓httpClient返回一個promise

function httpClient_promise(){

    return new Promise(function(resovle,reject){
        //模擬異步執(zhí)行
        setTimeout(function(){
            resovle("DONE~~~~~");
            //reject(new Error("failed"));
        },1000);
    });
}

function runHttpClient2(){
    httpClient_promise().then(function(result){
        console.log(">>>"+result);
    }).catch(function(error){
        console.err(error);
    });
}

runHttpClient2();

你的httpClient函數(shù)應(yīng)該返回一個promise對象，調(diào)用也應(yīng)該是 httpClient().then ，或者用 async/await 的寫法：

const httpClient = function () {
    const options = {
        // ...
    };
    return new Promise((resolve, reject) => {
        http.get(options, (res) => {
            // ...
            // 你的 error 哪去了？
            res.on('end', () => {
                resolve(tr)
            })
        })
    })
}


//調(diào)用-- async/await，基于promise
router.get('/', async (req, resp, next) => {  
    let promise = new Promise(async (resolve, reject)=>{
        const result = await httpClient();
    })
})