Javascript 嵌套保证了并行效果?
我必须在承诺中包含承诺,这可以吗,或者被认为是不好的做法Javascript 嵌套保证了并行效果?,javascript,promise,ecmascript-6,Javascript,Promise,Ecmascript 6,我必须在承诺中包含承诺,这可以吗,或者被认为是不好的做法 我有一个类,它有一个方法,fetchArticles,fetchImages,和main。 main是调用fetchArticles+fetchImages fetchArticles从另一个文件运行一个函数,该函数返回一个承诺,但我也在fetchArticles类方法本身上返回一个承诺,因此当它获取文章时,它将继续获取图像 fetchImages方法未承诺,但从另一个文件调用承诺的函数 我不确定这是否是实现parralel效果的最佳
fetchArticles
,fetchImages
,和main
。
是调用main
+fetchArticles
fetchImages
从另一个文件运行一个函数,该函数返回一个承诺,但我也在fetchArticles
类方法本身上返回一个承诺,因此当它获取文章时,它将继续获取图像fetchArticles
方法未承诺,但从另一个文件调用承诺的函数fetchImages
main () {
// Call the promised fetchArticles class method
this.fetchArticles()
.then ( () => this.fetchImages( () => {
this.res.json(this.articles.data);
}));
}
fetchArticles () {
return new Promise ((fullfil, rej) => {
// Calling a promised function which simply returns an array of articles
fetchArticles (this.parametersForApiCall)
.then ( (data) => {
this.articles.data = data;
this.articles.imageIds = [1,5,2,8,99,1000,22,44,55,120,241]; // Extract image IDS and save to class this
fullfil();
})
.catch ( (err) => {
console.log ("Something went wrong with api call", err);
res.json({error: "Something went wrong", code: 1011});
reject();
});
});
}
fetchImages (cb) {
// Calling a promised function which simply returns an array of images
fetchImages (this.imageIds).then( (imgs) => {
this.images = imgs;
cb (); // Temp callback method
}).catch ( (err) => {
console.log (err, "error finding images in then")
})
}
}
我应该使用类似异步并行的东西吗?注意:我在获取图像
方法中临时添加了一个回调
,直到找到链接承诺的好解决方案。似乎是的工作。似乎是的工作。注意:
fetchArticles
函数中创建了一个不必要的承诺。您可以直接返回promisified fetchArticles的结果main
函数fetchImages
函数中直接返回承诺。因为这也是承诺,所以您不再需要回调。我把它拿走了main () {
// Call the promised fetchArticles and fetchImages class methods
Promise.all([this.fetchArticles(), this.fetchImages()])
.then(() => this.res.json(this.articles.data));
}
fetchArticles () {
// Calling a promised function which simply returns an array of articles
return fetchArticles (this.parametersForApiCall)
.then ( (data) => {
this.articles.data = data;
this.articles.imageIds = [1,5,2,8,99,1000,22,44,55,120,241]; // Extract image IDS and save to class this
})
.catch ( (err) => {
console.log ("Something went wrong with api call", err);
res.json({error: "Something went wrong", code: 1011});
reject();
});
}
fetchImages () {
// Calling a promised function which simply returns an array of images
return fetchImages (this.imageIds).then( (imgs) => {
this.images = imgs;
}).catch ( (err) => {
console.log (err, "error finding images in then")
})
}
}
请注意:
fetchArticles
函数中创建了一个不必要的承诺。您可以直接返回promisified fetchArticles的结果main
函数fetchImages
函数中直接返回承诺。因为这也是承诺,所以您不再需要回调。我把它拿走了main () {
// Call the promised fetchArticles and fetchImages class methods
Promise.all([this.fetchArticles(), this.fetchImages()])
.then(() => this.res.json(this.articles.data));
}
fetchArticles () {
// Calling a promised function which simply returns an array of articles
return fetchArticles (this.parametersForApiCall)
.then ( (data) => {
this.articles.data = data;
this.articles.imageIds = [1,5,2,8,99,1000,22,44,55,120,241]; // Extract image IDS and save to class this
})
.catch ( (err) => {
console.log ("Something went wrong with api call", err);
res.json({error: "Something went wrong", code: 1011});
reject();
});
}
fetchImages () {
// Calling a promised function which simply returns an array of images
return fetchImages (this.imageIds).then( (imgs) => {
this.images = imgs;
}).catch ( (err) => {
console.log (err, "error finding images in then")
})
}
}
嵌套的承诺很好:)嵌套的承诺很好:)我决定接受你的承诺,因为它更详细!当然可以看看我的解释性编辑,其他一些可能会有用的信息。我决定接受你的,因为它更详细!当然可以看看我的解释性编辑,了解一些其他可能有用的信息。