I'm new to JavaScript and Promises. I need to send an array of requests using Promise.all
and await
. Unfortunately, I do not know the size of the array, so it needs to be dynamic. The array would be requests. Ex:
let arrayOfApiCreateRecords = [];
arrayOfApiCreateRecords.push(apiCreateRecords(req, { clientHeaders: headers, record }));
let responses = await Promise.all( arrayOfApiCreateRecords );
I tried to write my code like this, but I seem to be stuck. Is it possible to rewrite the code using Promise.all
and await with a dynamic array of requests? Please advise. Below is what I have:
'use strict';
const { apiCreateRecords } = require('../../../records/createRecords');
const createRecords = async (req, headers) => {
let body = [];
let status;
for(let i = 0; i < req.body.length; i++) {
let r = req.body[i];
let record = {
recordId: r.record_Id,
recordStatus: r.record_status,
};
const response = await apiCreateRecords(req, { clientHeaders: headers, record });
status = (status != undefined || status >= 300) ? status : response.status;
body.push(response.body);
};
return { status, body };
};
module.exports = {
createRecords,
};
Okay, I'm going to use fetch
API to demonstrate the usage of Promise.all()
Normal usage (for one fetch
call)
let user = { username: 'john.doe', password: 'secret' };
try{
let res = await fetch('https://example.com/user/', {
method: 'POST',
headers: {
'Content-Type': 'application/json'
},
body: JSON.stringify(user)
})
console.log('User creation response: ', res);
}
catch(err){
console.error('User creation error: ', err);
}
Now let's use Promise.all()
const users = [
{ username: 'john.doe', password: 'secret' },
{ username: 'jane.doe', password: 'i-love-my-secret' }
];
const requests = [];
// push first request into array
requests.push(
fetch('https://example.com/user/', {
method: 'POST',
headers: {
'Content-Type': 'application/json'
},
body: JSON.stringify(user[0])
})
);
// push second request into array
requests.push(
fetch('https://example.com/user/', {
method: 'POST',
headers: {
'Content-Type': 'application/json'
},
body: JSON.stringify(user[1])
})
);
try{
const responses = await Promise.all(requests);
console.log('User creation responses: ', responses);
}
catch(err){
console.log('User creation error: ', err);
}
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