CertainPerformance highlighted in my previous post advised me to avoid the explicit Promise construction antipattern with reference to to following question in stackoverflow
Frankly, Speaking, I am new to JS and node and I haven't used promise a lot. I went and read those article but either I was unable to comprehend or unable to relate or maybe somewhere my understanding of promises have been vague/wrong all together
So I decided to ask this question in a new thread and seek for help.
So what am I doing and why am I doing it
I am creating helper/common function which I could use to keep my code tidy and if in case I want to change anything inside function at anytime, I don't have to manually change every function.
So these are the functions I have made
//Find user by email Address
const findUserByEmail = (emailAddress) => {
return new Promise((resolve, reject) => {
User.findOne({email: emailAddress}).then(response => {
resolve(res)
}).catch(error => {
reject("Error in findUserByEmail", error);
})
})
}
//Create User
const createNewUser = (newUserDetails) => {
return new Promise((resolve, reject) => {
new User({
fullName: newUserDetails.fullName,
email: newUserDetails.email,
image: newUserDetails.image,
gender: newUserDetails.gender,
age: newUserDetails.age
}).save().then((response) => {
resolve(response)
}).catch((error) => {
reject("Problem in Creating New User", error)
})
})
}
Question 1
Now, I am assuming CertainPerformance said the excessive use of promises because I am creating new promise return new Promise((resolve, reject) => {
when I am already using promises with mongoose User.findOne({email: emailAddress}).then(response => {
?
But the reason for me to create those promise was, when I call these helper function from anywhere in my app after importing
const { findUserByEmail } = require("./my_db_query");
I would probably want it return a response or throw an error in case of error
findUserByEmail("test@example.com").then(/*...*/).catch(/*...*/);
If I change my above code snippet without adding new promise
function findUserByEmail (email) {
return User.findOne({email: email}).then(currentUser => currentUser).catch(error => error)
}
Question 2
Then I won't probably be able to .then
and .catch
in findUserByEmail("test@example.com")
?
And In API route of App, where I would be calling the findUserByEmail("test@example.com")
function, I would want to do something else if there is an error (which would be different for different case and hence I cannot use it in my helper function).
Question 3
Does, it make sense now for doing return new Promise((resolve, reject) => {
instead of doing just one return User.findOne(
or am I missing something?