I hope you can help me because it is HOURS of trying to get this problem resolved. I've googled so much and tried all of the solutions I found, but I keep getting the same error. I am trying to make an axis get a request to an API that is paginated for 1 result per page, loop through all of the results, and resolve the promises with the promise array. I have verified that without the loop, just getting 1 request, everything works. I have successful writing to MongoDB using MongoDB driver and its fine. Once I bring the loop in I cannot get the promises to resolve. I was able to console.log that the promise array does, indeed, have x number of pending promises in them.
const MongoClient = require('mongodb')
const axios = require('axios');
const url = 'https://catfact.ninja/fact'
let db = null;
let client = null;
//this one works great
const getMetaData = function () {
let data = axios.get(url+"s")
.then(response => {
return response.data
}).catch(error => console.log(error));
return data;
}
//this one will not resolve
const dataArray = async function (total) {
let baseUrl = url+"s/facts?page="
let res =[];
let promises = [];
for (let page = 1; page <= total; page++){
promises.push(axios.get(baseUrl+page))
}
axios.all(promises).then(result => console.log(result))
//originally i wanted to map the result to an array of json
//objects, but if i could even get a console.log it would be
//a win. spread operator not working, Promise.all not working
//i must have tried 12 different stackoverflow responses from
//other questions. until i can resolve the promises I can't do anything.
}
exports.connect = async function(url, done) {
if (db) return done();
// let data = await getMetaData()
// let total = data['total']
let arr = dataArray(5);
//console.log("arr is "+arr)
MongoClient.connect(url, {useNewUrlParser: true}, function (err, client){
if (err) return done(err);
client = client;
db = client.db('morefun');
/*
db.collection('catfacts').insertMany(dataArray, function(err, res){
if (err) throw err;
console.log("Inserted: " + res.insertedCount);
})*/
done();
});
}
exports.get = function() {
return db;
}
//make sure this is correct
exports.close = function(done) {
if (db) {
client.close(function(err, result) {
db = null;
mode = null;
done(err);
});
}
}
I need an array of JSON objects for the insertMany function to work. please someone help me. what am I doing wrong?
In the for loop, you are creating a URL like this: https://catfact.ninja/facts/facts?page=1
– this is incorrect, the correct URL should be https://catfact.ninja/facts?page=1
(with facts only once).
Also, the keyword async
is not needed here, and you should return the result of axios.all
.
A correct version of your code:
const dataArray = function (total) {
let baseUrl = url+"s?page="
let res =[];
let promises = [];
for (let page = 1; page <= total; page++){
promises.push(axios.get(baseUrl+page))
}
return axios.all(promises).then(result => {
console.log(result);
return result;
});
}
You can then get your data like this:
let arr = await dataArray(5);
Getting the actual data the way you want it
From your comments, I see that what you really want is to post-process the data obtained from the API to ultimately get one array that contains only the cat data.
You can do this by “massaging” the data with map and reduce , like this:
return axios
.all(promises)
.then(result => result.map(({ data }) => data.data).reduce((curr, acc) => acc.concat(curr), []));
Note: I've left out the console.log statement here for brevity.
We get a result that looks like this, which is hopefully what you want 😁:
[
{
"fact": "Cats see six times better in the dark and at night than humans.",
"length": 63
},
{
"fact": "The ability of a cat to find its way home is called “psi-traveling.” Experts think cats either use the angle of the sunlight to find their way or that cats have magnetized cells in their brains that act as compasses.",
"length": 220
},
{
"fact": "Cat's urine glows under a black light.",
"length": 38
},
{
"fact": "There are more than 500 million domestic cats in the world, with approximately 40 recognized breeds.",
"length": 100
},
{
"fact": "A tomcat (male cat) can begin mating when he is between 7 and 10 months old.",
"length": 76
}
]
不确定这是否是答案,但我知道当不使用axios想要完全用于axios的语法时,我遇到了问题。
axios.all([fetch1request(), fetch2request()]).then(axios.spread((fetch1, fetch2 ) => * whatever logic you need. But at this point the requests are complete* })
The technical post webpages of this site follow the CC BY-SA 4.0 protocol. If you need to reprint, please indicate the site URL or the original address.Any question please contact:yoyou2525@163.com.