I make a method that create a promise for each element in array.
queries.push(function (collection) {
new Promise((resolve, reject) => {
collection.find({}).limit(3).toArray(function (err, docs) {
if (err) reject(err);
resolve(docs);
});
});
});
const getAnalyticsPromises = (collection) => {
let promises = [];
queries.each((item) => {
promises.push(item(collection));
});
console.log(queries);
return promises;
}
This code return this errors:
(node:10464) UnhandledPromiseRejectionWarning: Unhandled promise rejection (rejection id: 1): TypeError: queries.each is not a function
(node:10464) DeprecationWarning: Unhandled promise rejections are deprecated. In the future, promise rejections that are not handled will terminate the Node.js process with a non-zero exit code.
The question is: When the promise is called? When i create it:
promises.push(item(collection));
or when i call it with then() function?
Well the error you have is about queries
has not method each
- you should use forEach
instead.
Bescides you should return promise from your function:
queries.push(function (collection) {
return new Promise((resolve, reject) => {
collection.find({}).limit(3).toArray(function (err, docs) {
if (err) reject(err);
resolve(docs);
});
});
});
So when you call item(collection)
where item
is one of your anonymous functions, the promise would be created.
And now you can handle with it whatever you need, for example:
let p = item(collection);
p.then(...).catch(...)