TypeError：response2.json 不是函数

Question

我正在尝试使用匿名函数来获取两个数据集。使用两个 fetch 调用第二个调用取决于第一个调用，第二个调用是一个循环我保持在第二个调用时出错 response2.json 不是函数

    async function example() {
    let response1 = await fetch(
        `https://www.flickr.com/services/rest/?method=flickr.photos.search&api_key=9c348b767f7a0403e907b0788188afba&text=observatory&accuracy=+11&media=photos+&geo_context=1&lat=41.8989&lon=-87.6123&radius=25&radius_units=km&extras=&format=json&nojsoncallback=1`
    );
    let json = await response1.json();
    console.log(json.photos.photo);

    const response2 = await json.photos.photo.map((i) =>
        fetch(
            `https://www.flickr.com/services/rest/?method=flickr.photos.geo.getLocation&api_key=9c348b767f7a0403e907b0788188afba&photo_id=${i.id}&format=json&nojsoncallback=1`
        )
    );


    const json2 = await response2.json();
    console.log(json2);
    return {
        dataset1: json,
        dataset2: json2
    };
}

Answer 1

问题

response2 是一系列承诺，

await json.photos.photo.map不会使内部请求同步，

const response2 = await json.photos.photo.map((i) =>
        fetch(
            `https://www.flickr.com/services/rest/?method=flickr.photos.geo.getLocation&api_key=9c348b767f7a0403e907b0788188afba&photo_id=${i.id}&format=json&nojsoncallback=1`
        )
    );

解决方案：

const promises = json.photos.photo.map((i) =>
    fetch(
        `https://www.flickr.com/services/rest/?method=flickr.photos.geo.getLocation&api_key=9c348b767f7a0403e907b0788188afba&photo_id=${i.id}&format=json&nojsoncallback=1`
    )
));

// get all response from promises
const response2 = await Promise.all(promises)

// response2 is array of responses , so we need to loop through it
const json2 = await Promise.all(response2.map(res => res.json()));

Answer 2

const response2 = await json.photos.photo.map(fetch('yourUrl'))

接下来await 是一个数组，而不是一个承诺 所以也许你可以使用 Promise.all 来包装这个数组。 但是fetch 比普通的承诺有点特别。

const response2 = await Promise.all(json.photos.photo.map(fetch('yourUrl')));
const responseVirtual = response2.map(res => res.json());

希望对你有帮助，兄弟