Develop Reference

Trying to understand Async/Await

I have an async function 'query' that 'awaits' for the pool.query to return the results.
// db.js
const pool = new pg.Pool({
connectionString: isProduction ? process.env.DATABASE_URL : connectionString,
ssl: isProduction,
});
export const query = async ({ text, values }) => {
const start = Date.now();
try {
const results = await pool.query(text, values);
const duration = Date.now() - start;
logger.info(`executed query: ${text} duration: ${duration} rows: ${results.rowCount}`);
return results.rows;
} catch (e) {
logger.error(`error: ${e}`);
}
};
In another async function getUser() I'm 'awaiting' the query function to finish before returning the data.
// users.js
export const getUser = async (email) => {
const text = `
SELECT (user_id, email) FROM users
WHERE email = $1
`;
const values = [email];
try {
const data = await query({ text, values });
// ^ vscode says above await is doing nothing
return data.rows[0];
} catch (e) {
logger.error(`error: ${e}`);
}
};
Then in yet another async function I'm awaiting the getUser function
// auth.js
export const SignIn = async (email, password) => {
const userRecord = await getUser(email);
if (!userRecord) {
throw new Error('User not registered');
}
logger.silly('Checking password');
const validPassword = await argon2.verify(userRecord.password, password);
if (validPassword) {
logger.silly('Password is valid!');
logger.silly('Generating JWT');
const token = await generateToken(userRecord);
const user = { id: userRecord.id, email: userRecord.email };
return { user, token };
} else {
throw new Error('Invalid Password');
}
};
Inside vsCode I'm getting a warning "await has no effect on the type of this expression." only when 'awaiting' the query function call, but not when 'awaiting' the getUser function call. What am I missing here?

What does query return? If results.rows is a promise then that might explain what you're seeing.

Testing blackboxed APIs in JS/Vue with jest

Well, I have an interesting case...
I'm trying to test a Vuex action that uses the Okta SDK to log in a User. Nothing special there. But at the testing level, I'm stuck trying to catch the idea. I mean, I just want to know if the functions have been called, not anything else, here the code:
The service:
const signIn = async ({ username, password }) => {
const response = await authClient.signIn({ username, password })
if (response.status === 'SUCCESS') {
const tokens = await authClient.token.getWithoutPrompt({
responseType: 'id_token',
sessionToken: response.sessionToken
})
authClient.tokenManager.add('idToken', tokens.tokens.idToken)
return response
}
}
The action:
async logIn({ commit }, { username, password }) {
const loginData = await signIn({ username, password })
commit(mutationTypes.setUserData, {
...loginData.user.profile
})
}
The test:
const authClient = {
signIn() {
return new Promise(resolve => resolve())
},
token: {
getWithoutPrompt() {
return new Promise(resolve => resolve())
}
},
tokenManager: {
add() {
return new Promise(resolve => resolve())
}
}
}
jest.mock('authClient', () => authClient)
it('Auth -> actions.signIn', async () => {
const commit = jest.fn()
const username = 'user'
const password = 'pass'
await actions.signIn({ commit }, { username, password })
expect(authClient.signIn).toHaveBeenCalled()
expect(authClient.token.getWithoutPrompt).toHaveBeenCalled()
expect(authClient.tokenManager.add).toHaveBeenCalled()
expect(commit).toHaveBeenCalled()
})

Where is my error in using promises in node.js

I am still very new to node.js. In my current test project I want to send a confirmation email or other emails, depending on the loaded template. The template is stored in MySQL.
The result I am getting is:
{
"message": {
"error": {},
"foo": "bar"
}
}
So the error bit is empty and I don't know why...
If I reject manually at a different point in the code it works just fine, so the problem is not with the middleware, router or server.js file.
Also I have rejected "Foo: Bar" back, to check which catch block catched the error.
Here is my mailer.js file:
const nodemailer = require('nodemailer');
let conDB;
module.exports = (injectedMySql) => {
conDB = injectedMySql
return {
sendMail: sendMail
}
}
const sendMail = (mail) => {
return new Promise((resolve,reject) => {
loadTemplate(mail.templateId, mail.languageId)
.then(data => {
const mailserver = {
host: "something.com",
port: 465,
secure: true, // use TLS
auth: {
user: "something#something.com",
pass: "PASSWORD"
},
tls: {
// do not fail on invalid certs
rejectUnauthorized: false
}
};
const body = {
from: 'something#something.com',
to: mail.toAdress,
subject: allReplace(data.subject, mail.subjectReplace),
text: allReplace(data.body, mail.textReplace),
html: allReplace(data.html, mail.htmlReplace)
}
// create a nodemailer transporter using smtp
let transporter = nodemailer.createTransport(mailserver)
transporter.sendMail(body)
.then(data => {console.log(data)
resolve(data)
})
.catch(err => {reject("sendMail problem")})
})
.catch(error => {reject({"error": error, "foo": "bar"})})
})
}
function allReplace (str, obj) {
var retStr = str;
for (var x in obj) {
retStr = retStr.replace(new RegExp(x, 'g'), obj[x]);
}
return retStr;
};
const loadTemplate = (mailTemplate, languageId) => {
return new Promise((resolve,reject) => {
if(mailTemplate === null || languageId === null)
reject("nop, something is missing");
else
{
if (typeof conDB.query === "function")
{
conDB.query('SELECT * FROM email_template WHERE language_id = ? AND template_id = ?', [mailTemplate,languageId])
.then(data => {resolve(data)})
.catch(err => {reject("mysql has a problem")})
}
else
{
reject("function is not available");
}
}
})
}
Here is my mysql.js file:
var mysql = require('mysql2/promise');
const databaseConfigs = {
host: 'localhost',
user: 'USERNAME',
password: 'PASSWORD',
database: 'DBNAME'
};
const createID = table => {
return new Promise((resolve,reject) => {
//execute the query to register the user
let query = '';
let id = Math.random().toString(36).substring(2, 15) + Math.random().toString(36).substring(2, 15)
query = `SELECT * FROM ${table} WHERE id = ?`
this.query(query,[table,id])
.then(data => {
console.log(data[0].length)
if(data[0].length==0)
{
resolve(id)
}
else
{
createID(table)
.then(data => {resolve(data)})
.catch(error => {reject(error)})
}
})
.catch(error => {reject(error)})
})
}
async function query (sql,att) {
let connection = await mysql.createConnection(databaseConfigs);
return new Promise( ( resolve, reject ) => {
console.log(`Query: '${sql}'`);
connection.query(sql,att)
.then(data => {resolve(data)})
.catch(error => {reject(error)})
connection.end();
});
}
async function transaction(queries, queryValues) {
if (queries.length !== queryValues.length) {
return Promise.reject(
'Number of provided queries did not match the number of provided query values arrays'
)
}
const connection = await mysql.createConnection(databaseConfigs)
try {
await connection.beginTransaction()
const queryPromises = []
queries.forEach((query, index) => {
queryPromises.push(connection.query(query, queryValues[index]))
})
const results = await Promise.all(queryPromises)
await connection.commit()
await connection.end()
return results
} catch (err) {
await connection.rollback()
await connection.end()
return Promise.reject(err)
}
}
module.exports.transaction = transaction;
module.exports.query = query;
module.exports.createID = createID;
Thanks to you all!
Chris

I cleand up your code a bit. Specially the error handling as you always mask your errors with your Promise.reject("message").
I think what confused you is that you're already using libraries which work with promise (you don't need to wrap those into promises again). Thats quite good as you just can use async/await then.
I hope it helps. If something is unclear just ask.
const nodemailer = require('nodemailer');
let conDB;
module.exports = (injectedMySql) => {
conDB = injectedMySql
return {
sendMail: sendMail
}
}
// your load template function already uses promises no need to wrap it
const sendMail = async mail => {
const data = await loadTemplate(mail.templateId, mail.languageId)
const mailserver = {
host: "something.com",
port: 465,
secure: true, // use TLS
auth: {
user: "something#something.com",
pass: "PASSWORD"
},
tls: {
// do not fail on invalid certs
rejectUnauthorized: false
}
};
const body = {
from: 'something#something.com',
to: mail.toAdress,
subject: allReplace(data.subject, mail.subjectReplace),
text: allReplace(data.body, mail.textReplace),
html: allReplace(data.html, mail.htmlReplace)
}
// create a nodemailer transporter using smtp
let transporter = nodemailer.createTransport(mailserver)
try {
// Return the value of sendmail
return await transporter.sendMail(body);
} catch (err) {
// handle error or throw it. I'll throw as you rejected the Promise here it.
// this part will actually help you as you now can see the correct error instead of your rejected "foo bar" erro object
throw err;
}
}
function allReplace(str, obj) {
var retStr = str;
for (var x in obj) {
retStr = retStr.replace(new RegExp(x, 'g'), obj[x]);
}
return retStr;
};
const loadTemplate = async (mailTemplate, languageId) => {
if (mailTemplate === null || languageId === null)
throw new Error("nop, something is missing");
else {
if (typeof conDB.query === "function") {
try {
const data = await conDB.query('SELECT * FROM email_template WHERE language_id = ? AND template_id = ?', [mailTemplate, languageId]);
} catch (err) {
// it's better to use the real error you always hide the real reason why something went wrong with your promise reject :).
throw err;
}
}
else {
throw new error("function is not available");
}
}
}
.
var mysql = require('mysql2/promise');
const databaseConfigs = {
host: 'localhost',
user: 'USERNAME',
password: 'PASSWORD',
database: 'DBNAME'
};
const createID = async table => {
// use GUID? https://www.npmjs.com/package/guid
let id = Math.random().toString(36).substring(2, 15) + Math.random().toString(36).substring(2, 15)
let query = `SELECT * FROM ${table} WHERE id = ?`
try {
data = await this.query(query, [table, id]);
} catch (error) {
// as we throw the error in query we got to catch it here
// handle it or throw it (I throw it because I can't handle it ;).)
throw error;
}
console.log(data[0].length)
if (data[0].length == 0) {
return id;
} else {
return await createID(table);
}
}
const query = async (sql, att) => {
let connection = await mysql.createConnection(databaseConfigs);
console.log(`Query: '${sql}'`);
try {
const data = await connection.query(sql, att);
return data;
} catch (error) {
// Handle error or throw it again
// you rejected the promise so i throw it here
throw error;
} finally {
connection.end();
}
}
// I changed it to make it the same as the other functions from this
// async function transaction(queries, queryValues) { to
const transaction = async (queries, queryValues) => {
if (queries.length !== queryValues.length) {
// just throw an error
throw new Error('Number of provided queries did not match the number of provided query values arrays');
}
const connection = await mysql.createConnection(databaseConfigs)
try {
await connection.beginTransaction()
const queryPromises = []
queries.forEach((query, index) => {
queryPromises.push(connection.query(query, queryValues[index]))
})
const results = await Promise.all(queryPromises)
await connection.commit()
await connection.end()
return results
} catch (err) {
await connection.rollback()
await connection.end()
// this is not needed
// return Promise.reject(err)
// if you don't want to handle it here just throw the error
throw err;
}
}
module.exports.transaction = transaction;
module.exports.query = query;
module.exports.createID = createID;

Jest mock function not working as expected

I'm trying to create a mock for a function createClient where it should return a specific object.
However, for some reason the mock is ignored and it runs the function instead of receiving the mock value.
authorization.js
// some requires here
const createClient = req => {
if (!(req.user && req.user.access_token)) {
throw new Error('Not authorized');
}
...
return { ... }
}
const getUser = async client => { ... }
module.exports = options => {
...
createClient(req) is called here
...
}
authorization.test.js
import authorization from '../../server/middlewares/authorization';
describe('authorization.js', () => {
it('Should do something', async done => {
authorization.createClient = jest.fn(() => ({
client: 'test',
}));
// ACT
const authorizationMiddleware = authorization();
const result = await authorizationMiddleware(someOptions);
// ASSERT
expect(result).toBe('authorized');
done();
});
The error
It seems that the mock for createClient is not working as I wanted to be. It should return the object { client: 'test' }

Your code is incomplete, so I try to give a demo for your case. If you want to mock a private variable in the module scope, the createClient function for your case. You can use rewire package to do that.
E.g.
authorization.js
let createClient = (req) => {
if (!(req.user && req.user.access_token)) {
throw new Error('Not authorized');
}
function getUser() {
return 'real user';
}
return { getUser };
};
const getUser = async (client) => {
return client.getUser();
};
module.exports = (options) => {
const client = createClient(options.req);
return () => getUser(client);
};
authorization.test.js:
const rewire = require('rewire');
describe('61076881', () => {
it('should get user', async () => {
const authorization = rewire('./authorization');
const mClient = { getUser: jest.fn().mockReturnValueOnce('fake user') };
const mCreateClient = jest.fn(() => mClient);
authorization.__set__('createClient', mCreateClient);
const options = { req: { user: { access_token: '123' } } };
const authorizationMiddleware = authorization(options);
const user = await authorizationMiddleware();
expect(user).toEqual('fake user');
expect(mCreateClient).toBeCalledWith(options.req);
expect(mClient.getUser).toBeCalledTimes(1);
});
});
unit test results:
PASS stackoverflow/61076881/authorization.test.js (7.601s)
61076881
✓ should get user (10ms)
Test Suites: 1 passed, 1 total
Tests: 1 passed, 1 total
Snapshots: 0 total
Time: 8.54s, estimated 9s
source code: https://github.com/mrdulin/react-apollo-graphql-starter-kit/tree/master/stackoverflow/61076881

Server keeps getting old result

After adding a user, the new user is not shown in the list. Everything works only after restarting the server. It looks like the server is downloading data from the cache memory. Maybe my code is not written properly. How to get current data from the database?
// addFile
const sqlite3 = require("sqlite3").verbose();
const db = new sqlite3.Database("./db/dbSqlite/app.db", sqlite3.OPEN_READWRITE);
const add = (user) => {
return new Promise((res, rej) => {
db.serialize(() => {
let status = false;
db.run(`INSERT INTO users(
login,
password,
) VALUES(?, ?)`, user, (err) => {
if (err) rej(status);
status = true;
res(status);
});
})
})
}
module.exports = add;
// getAll file
const sqlite3 = require("sqlite3").verbose();
const db = new sqlite3.Database("./db/dbSqlite/app.db");
const getAll = new Promise((res, rej) => {
db.all(`SELECT * from users`, (err, row) => {
if (row === undefined || err) {
res("NO_TABLE_USERS");
} else {
const stringified = JSON.stringify(row)
res(JSON.parse(stringified));
}
});
})
module.exports = getAll
// route
router.post("/add", helper.isLoggedIn, helper.isAdmin, (req, res) => {
let msg = "User created successfully!";
user.add(Object.values(req.body)
.then((state) => {
if (!state) msg = "Name already used!";
user.getAll
.then((result) => res.render("users", {
name: req.user,
users: result,
msg: msg
}));
}));
});

getAll should be a function, like you did with add. Otherwise, getAll will be resolved once :
// addFile
const sqlite3 = require("sqlite3").verbose();
const db = new sqlite3.Database("./db/dbSqlite/app.db", sqlite3.OPEN_READWRITE);
const add = (user) => {
return new Promise((res, rej) => {
db.serialize(() => {
let status = false;
db.run(`INSERT INTO users(
login,
password,
) VALUES(?, ?)`, user, (err) => {
if (err) rej(status);
status = true;
res(status);
});
})
})
}
module.exports = add;
// getAll file
const sqlite3 = require("sqlite3").verbose();
const db = new sqlite3.Database("./db/dbSqlite/app.db");
const getAll = () => {
return new Promise((res, rej) => {
db.all(`SELECT * from users`, (err, row) => {
if (row === undefined || err) {
res("NO_TABLE_USERS");
} else {
const stringified = JSON.stringify(row)
res(JSON.parse(stringified));
}
});
});
}
module.exports = getAll
// route
router.post("/add", helper.isLoggedIn, helper.isAdmin, (req, res) => {
let msg = "User created successfully!";
user.add(Object.values(req.body)
.then((state) => {
if (!state) msg = "Name already used!";
user.getAll()
.then((result) => res.render("users", {
name: req.user,
users: result,
msg: msg
}));
}));
});