javascript - 如何停止 Promise 对象的自动解析？

Question

考虑这段代码:

function foo() {
    return promiseFoo.then((res) => {
        //...
        //Construct a `promiseBar` object which is promise-like, 
        //but also has other uses.
        //...
        return promiseBar;
    });
}

foo().then((res) => {
    //Because `promiseBar` is promise-like, it was automatically resolved.
    //So now, `res` is, for example, a primitive string instead of the 
    //original `promiseBar` object
})

有什么方法可以防止自动解析类似 promise 的对象吗？

Answer 1

你会把它包装在一个容器对象中，然后用解构打开它:

function foo() {
    return promiseFoo.then((res) => {
        //...
        //Construct a `promiseBar` object which is promise-like, 
        //but also has other uses.
        //...
        return [promiseBar];
    });
}

foo().then(([res]) => {
    //Because it is an array, promiseBar is not resolved here
});

公平地说，在使用 promises 的几年里，我从来没有真正需要自己这样做，所以我想知道你实际上在做什么 - 请分享。