javascript - 等待 ".then"解决

Question

我一直对“然后”不被等待的行为感到困扰，我明白其原因。然而，我仍然需要绕过它。这是我的用例。

doWork(family) {
    return doWork1(family)
            .then(resultOfWork1 => doWork2(resultOfWork1));
}

doWork1(family) {
   if (1 === family) {
       return doFamily1();
   } else {
       return doFamily2();
   }
}

doFamily1() {
    return $http(urlToFamily1)
            .then(response => parseFamily1Result(response));
}

parseFamily1Result(response) {
    return parsed response in a family1 way;
}

doFamily2() {
    return $http(urlToFamily2)
            .then(response => parseFamily2Result(response));
}

parseFamily2Result(response) {
   return parsed response in a family2 way;
}

doWork2(resultOfWork1) {
    // use resultOfWork1
}

我正在做的事情的问题是，在 doWork2 中，resultOfWork1 未定义，因为在到达 doWork2 之前不需要执行“then” promise 。

有没有办法保证“然后”的实现？或者说这种做事方式有什么问题吗？

Answer 1

您错误地链接了 Promise。

而不是

doWork(family) {
    return doWork1(family)
            .then(doWork2(resultOfWork1));
}

更改为

doWork(family) {
    return doWork1(family)
            .then(function(resultOfWork1){ doWork2(resultOfWork1); });
}

或者

doWork(family) {
    return doWork1(family)
            .then(doWork2);
}

您还需要对以下代码进行类似的更改。

$http(urlToFamily1)
            .then(parseFamily1Result(response));

$http(urlToFamily2)
            .then(parseFamily2Result(response));