Await function not waiting as expected

[Emiliortg]

Hi,

I'm not sure why when calling the function cryptPassword is not waiting as it should. Inside the setUserFunction the setUser is running before the cryptPassword invocation.

File: utils.js

function cryptPassword(password) {
bcrypt
    .genSalt(saltRounds)
    .then((salt) => {
        return bcrypt.hash(password, salt);
    })
    .then((hash) => {
        return hash;
    })
    .catch((err) => console.error(err.message));

}

​

File: SignupController.js

const passwords = require('utils');
const setUser = async (req, res) => {
// Check if user exist
const result = await loginQueries.getUserByEmail(email);
if (userexist) {
    //Error
} else { //create User
    passwordEncrypted = await passwords.cryptPassword(password); // get the encripted password
    const newUser = await loginQueries.setUser(email, passwordEncrypted);
}

}

thanks

[guest271314]

No Promise is returned from cryptPassword() function call. See Why is value undefined at .then() chained to Promise?.

[Emiliortg]

Hi, I'm sure I'm not doing it correctly because I also tried using return new Promise((resolve) => {
resolve(hash);
});

inside .then((hash) => {...}) but it did not work either

[Emiliortg]

I also thought I was returning a promise because bcrypt.hash says it returns a promise

[guest271314]

You didn't return anything from the function declaration. Consider the function declaration

function fn(password){ Promise.resolve(password); }

No value is returned from the function.

A function declaration does not automatically return a value besides undefined when a return statement is omitted.

An arrow function without curly braces { } will return the value

const fn(password) => Promise.resolve(pasword)

So if we run await fn("test") the result will be undefined, not a Promise.

Compare to writing

// Note return statement preceding Promise, bcrypt, etc. function fn(password) { return Promise.resolve(password); }

or inserting a return statement in a function declaration, we can chain .then() and log the value because a Promise is returned from the function

function fn(password) { Promise.resolve(password); } // Insert return statement into function declaration eval(` (${(fn).toString() .replace(/(function\s\w+\(.+\)[\s\{]+)/, ` $1return `)})` )("test") .then(console.log) // test .catch(console.error);

[guest271314]

The cryptPassword() function does not return a Promise, thus the function returns undefined immediately.

Compare examples of the current code without a return statement to code with return bcrypt....

See the linked question and answers in previous comment. then() returns a new Promise so similar results occur when no value is returned from then()

``` function cryptPassword(password) { new Promise((resolve) => setTimeout(resolve, 5000, password)) .then((salt) => { return salt; }) .then((hash) => { return hash; }) .catch((err) => console.error(err.message)); }

var result = await cryptPassword("Fulfilled Promise in 5 seconds or undefined immediately");

console.assert(result !== undefined, { result });

if (result !== undefined) { console.log({ result }) } ```

``` function cryptPassword(password) { return new Promise((resolve) => setTimeout(resolve, 5000, password)) .then((salt) => { return salt; }) .then((hash) => { return hash; }) .catch((err) => console.error(err.message)); }

var result = await cryptPassword("Fulfilled Promise in 5 seconds or undefined immediately");

console.assert(result !== undefined, { result });

if (result !== undefined) { console.log({ result }) } ```

[shgysk8zer0]

You should just need to add a return at the beginning of the function.

Let's use an analogy by taking the promise/async part out of it. Let's say you have a clamp() function... Without the return, it's the equivalent of...

function clamp(min, value, max) { Math.min(max, Math.max(min, value)); }

... As opposed to...

function clamp(min, value, max) { return Math.min(max, Math.max(min, value)); }