英文:
Async function does not return a response
问题
以下是翻译好的部分：
我是新手学习`Javascript`。我正在尝试读取一些文件并构造一个`JSON`对象响应。我能够运行整个代码，但还有一个最后的问题，我没有从`async`函数中获取到响应。
```lang-js
const path = require('path')
const fs = require('fs/promises');
const getProductDetailByProductID = async (id) => {
const productsFile = path.join(__dirname, 'turing_tasks', 'products.json')
const customersFile = path.join(__dirname, 'turing_tasks', 'customers.json')
const reviewsFile = path.join(__dirname, 'turing_tasks', 'reviews.json')
const imagesFile = path.join(__dirname, 'turing_tasks', 'images.json')
const { products } = JSON.parse(await fs.readFile(productsFile, 'utf-8'))
const product = products.filter(product => product.id === id)[0]
const {reviews} = JSON.parse(await fs.readFile(reviewsFile, 'utf-8'))
const {customers} = JSON.parse(await fs.readFile(customersFile, 'utf-8'))
const {images} = JSON.parse(await fs.readFile(imagesFile, 'utf-8'))
const reviewsData = []
reviews.forEach((review) => {
customer = customers.filter(customer => customer.id === review.customer_id)
if(customer) customer = customer[0]
const reviewImages = images.filter(image => review.images.includes(image.id))
reviewsData.push({
"id": review.id,
"rating": review.rating,
"customer": customer,
"images": reviewImages
})
})
return {
"id": product.id,
"name": product.name,
"reviews": reviewsData
}
}
(async () => {
const result = await getProductDetailByProductID(1);
return result
})(); // 这里没有获取到任何内容
我正在使用以下命令运行此文件
nodemon task.js
另外，如果这段代码写得不够好，也请推荐更好的写法。如果可能的话，请分享相关链接。
<details>
<summary>英文:</summary>
I am new to `Javascript`. I am trying to read a few files and construct a `JSON` object response. I am able to run the entire code, however, one last piece is remaining, I am not getting a response from the `async` function.
```lang-js
const path = require('path')
const fs = require('fs/promises');
const getProductDetailByProductID = async (id) => {
const productsFile = path.join(__dirname, 'turing_tasks', 'products.json')
const customersFile = path.join(__dirname, 'turing_tasks', 'customers.json')
const reviewsFile = path.join(__dirname, 'turing_tasks', 'reviews.json')
const imagesFile = path.join(__dirname, 'turing_tasks', 'images.json')
const { products } = JSON.parse(await fs.readFile(productsFile, 'utf-8'))
const product = products.filter(product => product.id === id)[0]
const {reviews} = JSON.parse(await fs.readFile(reviewsFile, 'utf-8'))
const {customers} = JSON.parse(await fs.readFile(customersFile, 'utf-8'))
const {images} = JSON.parse(await fs.readFile(imagesFile, 'utf-8'))
const reviewsData = []
reviews.forEach((review) => {
customer = customers.filter(customer => customer.id === review.customer_id)
if(customer) customer = customer[0]
const reviewImages = images.filter(image => review.images.includes(image.id))
reviewsData.push({
"id": review.id,
"rating": review.rating,
"customer": customer,
"images": reviewImages
})
})
return {
"id": product.id,
"name": product.name,
"reviews": reviewsData
}
}
(async () => {
const result = await getProductDetailByProductID(1);
return result
})(); // This does not fetch anything
I am running this file using below command
nodemon task.js
Also, please recommend a better way of writing this code if it is poorly written. Please share a link for the same.
答案1
得分: 0
因为您的getProductDetailByProductID是异步的，您应该像这样调用它：
(async () => {
const result = await getProductDetailByProductID(1);
console.log(result);
})();
更多信息：
getProductDetailByProductID // 此函数是异步的，并返回一个Promise值
如果您想要获取值：
async function ss() {
const result = await getProductDetailByProductID(1);
console.log(result); // 您的`getProductDetailByProductID`的返回值
return result;
}
ss()
如果您仍然要从异步函数中返回值，还需要使用async/await来获取值：
async function s2() {
const result = await ss();
console.log(result);
}
英文:
because your getProductDetailByProductID is async, you should call your getProductDetailByProductID like this:
(async () => {
const result = await getProductDetailByProductID(1);
console.log(result);
})();
more:
getProductDetailByProductID // this function is async and return a Promise value
if you want get the value:
function ss () {
const result = await getProductDetailByProductID(1);
console.log(result); // your getProductDetailByProductID's return value
return result;
}
ss()
if you still return value from async function, also need use async await to get value
sync function s2() {
const result = await ss();
console.log(result);
}
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