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How to stub a dependency in express middleware (express-validator/mocha/chai/sinon/proxyquire)

**Edit: Re-written with a simple example that works first:
So I've got a test file and 2 modules.
moduleA has a dependency, moduleB
// moduleA.js
const ModuleB = require('./moduleB');
function functionA() {
return 20 + ModuleB.functionB();
};
module.exports = { functionA };
// moduleB.js
const functionB = () => {
return 10;
}
module.exports = { functionB }
My test file stubs out functionB (returned from moduleB) using proxyquire:
const sinon = require('sinon');
const proxyquire = require('proxyquire');
describe('Unit Tests', function() {
it('should work', () => {
const mockedFn = sinon.stub();
mockedFn.returns(30);
const copyModuleA = proxyquire('./moduleA', {
'./moduleB': {
functionB: mockedFn
}
});
console.log(copyModuleA.functionA());
})
});
So it outputs 50 (stubbed functionB 30 + functionA 20)
Now I'm trying to take this example into my code:
moduleA in this case is a file called validation.js. It is dependent on moduleB, in this case a sequelize model, Person, with the function I want to mock: findOne
validation.js exports module.exports = { validateLogin };, a function that calls validate, which returns a function that uses Person.findOne()
So in my mind, as with the simple example, I need to create a stub, point to the validation module in proxyquire, and reference the dependency and its findOne function. Like this:
const stubbedFindOne = sinon.stub();
stubbedFindOne.resolves();
validationModule = proxyquire('../../utils/validation', {
'../models/Person': {
findOne: stubbedFindOne
}
});
This should stub Person.findOne in validation.js. But it doesn't seem to. And I have no idea why.
let validationModule;
describe('Unit Tests', () => {
before(() => {
const stubbedFindOne = sinon.stub();
stubbedFindOne.resolves();
validationModule = proxyquire('../../utils/validation', {
'../models/Person': {
findOne: stubbedFindOne
}
});
})
it.only('should return 422 if custom email validation fails', async() => {
const wrongEmailReq = { body: {email: 'nik#hotmail.com'} };
const res = {
statusCode: 500,
status: (code) => {this.statusCode = code; return this},
};
const validationFn = validationModule.validateLogin();
const wrongEmail = await validationFn(wrongEmailReq, res, ()=>{});
expect(wrongEmail.errors[0].msg).to.be.equal('Custom Authorisation Error');
return;
})
And this is my validation.js file:
const Person = require('../models/Person');
// parallel processing
const validate = validations => {
return async (req, res, next) => {
await Promise.all(validations.map(validation => validation.run(req)));
const errors = validationResult(req);
if (errors.isEmpty()) {
return next();
}
const error = new Error();
error.message = process.env.NODE_ENV === 'development'? 'Validation Failed':'Error';
error.statusCode = !errors.isEmpty()? 422:500;
error.errors = errors.array({onlyFirstError: true});
next(error);
return error;
};
};
const validateLogin = () => {
const validations = [
body('email')
.isString()
// snip
.custom(async (value, {req}) => {
try{
const person = await Person.findOne({ where: { email: value } });
if(!person) return Promise.reject('Custom Authorisation Error');
} catch(err) {
throw err;
}
})
.trim(),
];
return validate(validations);
}
module.exports = {
validateLogin
};

So the code in both the small sample and my app is correct, apart from how I stub the function. It shouldn't resolve or reject anything (I tried both out of desperation). It should return null in order to satisfy the conditional rather than jump to the catch block:
try{
const person = await Person.findOne({ where: { email: value } });
if(!person) return Promise.reject('Custom Authorisation Error');
} catch(err) {
throw err;
}
Hope the simple example helps someone else with proxyquire though

Encountering a problem when trying to remove some code from a route to put it into a service - Node.js / Express.js

I'm having a problem right now when i want to remove some code out of my route to put it into a service. I'm just trying to follow the best practices of developing an application.
This is my route right now:
const express = require('express');
const cityRouter = express.Router();
const axios = require('axios');
const NodeCache = require('node-cache');
const myCache = new NodeCache();
cityRouter.get('/:cep', async (request, response) => {
try {
const { cep } = request.params;
const value = myCache.get(cep);
if (value) {
response.status(200).send({
city: value,
message: 'Data from the cache',
});
} else {
const resp = await axios.get(`https://viacep.com.br/ws/${cep}/json/`);
myCache.set(cep, resp.data, 600);
response.status(200).send({
city: resp.data,
message: 'Data not from the cache',
});
}
} catch (error) {
return response.status(400);
}
});
module.exports = cityRouter;
I'm using axios to retrieve data from an API, where i have a variable called "cep" as a parameter and then using node-cache to cache it.
And it works with out problems:
enter image description here
But, when i try to put the same code into a service, and then call it into my route:
My service:
const axios = require('axios');
const NodeCache = require('node-cache');
const myCache = new NodeCache();
function verificaCache(cep) {
return async function (request, response, next) {
const value = myCache.get(cep);
console.log(cep);
if (value) {
response.status(200).send({
city: value,
message: 'Data from the cache',
});
} else {
const resp = await axios.get(`https://viacep.com.br/ws/${cep}/json/`);
myCache.set(cep, resp.data, 600);
response.status(200).send({
city: resp.data,
message: 'Data not from the cache',
});
}
next();
};
}
module.exports = verificaCache;
My route using the service:
const express = require('express');
const cityRouter = express.Router();
const verificaCache = require('../services/VerificaCacheService');
cityRouter.get('/:cep', async (request, response) => {
const { cep } = request.params;
verificaCache(cep);
response.status(200);
});
module.exports = cityRouter;
By some reason, it doesn't work:
enter image description here
What is the problem that i can't see? I'm a beginner so i'm kinda lost right now.

You have created a high-order function by returning a function in verificaCache(), so to properly call it you need to do it like that await verificaCache(cep)(req, res), remember, the first time you call it, you have a function being returned, since you want the tasks inside of that function to be executed, you need to call it as well.
Take a reading about high-order functions here: https://blog.alexdevero.com/higher-order-functions-javascript/
My recommendation, you could just get rid of the other function you are returning to simplify your code, and let the service only handle business logic, all the http actions should be handled on the controller level:
// Service
function verificaCache(cep) {
const value = myCache.get(cep);
if (value) {
return { city: value, message: 'Data from the cache'})
}
// No need of an else statement because the
// execution will stop at the first return if the condition passes
const resp = await axios.get(`https://viacep.com.br/ws/${cep}/json/`);
myCache.set(cep, resp.data, 600);
return { city: resp.data, message: 'Data not from the cache'};
}
// Controller
cityRouter.get('/:cep', async (request, response) => {
const { cep } = request.params;
try {
const data = verificaCache(cep);
// Use json() instead of send()
response.status(200).json(data);
} catch(error) {
// Handle errors here
console.log(error);
}
});
Estamos juntos!

Mocking Secrets Manager module for JavaScript jest unit tests

I'm having trouble getting the AWS Secrets Manager module mocked for the jest unit tests... The part it errors on is the .promise(). When I remove that, the code doesn't work for the real Secrets Manager so I think it needs to stay there. How do I mock the getSecretData function so that getSecretData.promise() will work for the mock?
Here is the SecretsManager.js code:
import AWS from 'aws-sdk';
export class SecretsManager {
constructor() {
AWS.config.update({
region: 'us-east-1',
});
this.secretsManager = new AWS.SecretsManager();
}
async getSecretData(secretName) {
try {
const response = await this.secretsManager.getSecretValue({
SecretId: secretName,
}).promise();
const secretString = response.SecretString;
const parsedSecret = JSON.parse(secretString);
return parsedSecret;
} catch (e) {
console.log('Failed to get data from AWS Secrets Manager.');
console.log(e);
throw new Error('Unable to retrieve data.');
}
}
}
Here is the SecretsManager.test.js code:
import { SecretsManager } from '../utils/SecretsManager';
jest.mock('aws-sdk', () => {
return {
config: {
update(val) {
},
},
SecretsManager: function () {
return {
async getSecretValue({
SecretId: secretName
}) {
return {
promise: function () {
return {
UserName: 'test',
Password: 'password',
};
}
};
}
};
}
}
});
describe('SecretsManager.js', () => {
describe('Given I have a valid secret name', () => {
describe('When I send a request for test_creds', () => {
it('Then the correct data is returned.', async () => {
const mockReturnValue = {
UserName: 'test',
Password: 'password',
};
const logger = getLogger();
const secretManager = new SecretsManager();
const result = await secretManager.getSecretData('test_creds');
expect(result).toEqual(mockReturnValue)
});
});
describe('When I send a request without data', () => {
it('Then an error is thrown.', async () => {
const secretManager = new SecretsManager();
await expect(secretManager.getSecretData()).rejects.toThrow();
});
});
});
});
This is the error I get when running the tests:
this.secretsManager.getSecretValue(...).promise is not a function
Any suggestions or pointers are greatly appreciated!
Thank you for looking at my post.

I finally got it to work... figures it'd happen shortly after posting the question, but instead of deleting the post I'll share how I changed the mock to make it work incase it helps anyone else.
Note: This is just the updated mock, the tests are the same as in the question above.
// I added this because it's closer to how AWS returns data for real.
const mockSecretData = {
ARN: 'x',
Name: 'test_creds',
VersionId: 'x',
SecretString: '{"UserName":"test","Password":"password"}',
VersionStages: ['x'],
CreatedDate: 'x'
}
jest.mock('aws-sdk', () => {
return {
config: {
update(val) {
},
},
SecretsManager: function () {
return {
getSecretValue: function ( { SecretId } ) {
{
// Adding function above to getSecretValue: is what made the original ".promise() is not a function" error go away.
if (SecretId === 'test_creds') {
return {
promise: function () {
return mockSecretData;
}
};
} else {
throw new Error('mock error');
}
}
}
};
}
}});

I ran into this issue as well. There may be a more elegant way to handle this that also allows for greater control and assertion, but I haven't found one. Note that the in-test option may work better with newer versions of Jest.
I personally solved this issue by making use of manual mocks and a custom mock file for aws-sdk. In your case, it would look something like the following:
# app_root/__tests__/__mocks__/aws-sdk.js
const exampleResponse = {
ARN: 'x',
Name: 'test_creds',
VersionId: 'x',
SecretString: '{"UserName":"test","Password":"password"}',
VersionStages: ['x'],
CreatedDate: 'x'
};
const mockPromise = jest.fn().mockResolvedValue(exampleResponse);
const getSecretValue = jest.fn().mockReturnValue({ promise: mockPromise });
function SecretsManager() { this.getSecretValue = getSecretValue };
const AWS = { SecretsManager };
module.exports = AWS;
Then in your test file:
// ... imports
jest.mock('aws-sdk');
// ... your tests
So, in a nutshell:
Instead of mocking directly in your test file, you're handing mocking control to a mock file, which Jest knows to look for in the __mocks__ directory.
You create a mock constructor for the SecretsManager in the mock file
SecretsManager returns an instance with the mock function getSecretValue
getSecretValue returns a mock promise
the mock promise returns the exampleResponse
Bada boom, bada bing. You can read more here.

I ran into a same issue, I have tried to solve as below. It worked perfectly in my case.
Terminalsecret.ts
import AWS from 'aws-sdk';
AWS.config.update({
region: "us-east-1",
});
const client = new AWS.SecretsManager();
export class Secret {
constructor(){}
async getSecret(secretName: string) {
let secret: any;
const data = await client.getSecretValue({ SecretId: secretName).promise();
if ('SecretString' in data) {
secret = data.SecretString;
} else {
const buff = Buffer.alloc(data.SecretBinary as any, 'base64');
secret = buff.toString('ascii');
}
const secretParse = JSON.parse(secret);
return secretParse[secretName];
}
}
Terminalsecret.test.ts
import { SecretsManager as fakeSecretsManager } from 'aws-sdk';
import { Secret } from './terminalSecret';
jest.mock('aws-sdk');
const setup = () => {
const mockGetSecretValue = jest.fn();
fakeSecretsManager.prototype.getSecretValue = mockGetSecretValue;
return { mockGetSecretValue };
};
describe('success', () => {
it('should call getSecretValue with the argument', async () => {
const { mockGetSecretValue } = setup();
mockGetSecretValue.mockReturnValueOnce({
promise: async () => ({ SecretString: '{"userName": "go-me"}' })
});
const fakeName = 'userName';
const terminalSecretMock: TerminalSecret = new TerminalSecret()
terminalSecretMock.getTerminalSecret(fakeName);
expect(mockGetSecretValue).toHaveBeenCalledTimes(1);
});
});

Code not executed after PUT route using Express

I listen to the chat event of the tmijs library, upon the !overlay chat I want to execute some code. What I want to achieve upon getting that message is:
Fetch the user
Check if the user has enough currency
Deduct currency from the user
Trigger a socket event to my react app
Everything seems to work up until the last bullet point. In my terminal it's shown that my user gets currency (called 'kluiten' in my code) deducted, but all the code that comes after it doesn't get executed.
require('dotenv').config();
const PORT = process.env.PORT || 9000;
class TwitchAPI {
constructor({io}) {
this.io = io;
this.client = new tmi.client(options);
this.client.connect();
this.handleOverlayRequest = this.handleOverlayRequest.bind(this);
this.handleChatMessage = this.handleChatMessage.bind(this);
this.client.on('chat', this.handleChatMessage);
}
handleChatMessage (channel, userstate, message) {
if(message === '!overlay') this.handleOverlayRequest(channel, userstate);
}
async handleOverlayRequest (channel, userstate) {
const requiredKluiten = 5;
const rawFoundUser = await fetch(`http://localhost:${PORT}/api/users/${userstate.username}`);
const foundUser = await rawFoundUser.json();
if(foundUser.instakluiten >= requiredKluiten) {
this.client.action(channel, `${userstate[`display-name`]}, you've got enough instakluiten for this.`);
const method = `PUT`;
const payload = { 'requiredKluiten': requiredKluiten };
const body = JSON.stringify(payload);
const headers = { 'Content-Type': `application/json; charset=utf-8` };
const result = await fetch(`http://localhost:${PORT}/api/users/${userstate.username}/decrementKluiten`, { method, body, headers });
console.log(result);
}
}
}
module.exports = TwitchAPI;
I then have an Express router:
const express = require('express');
const userController = require('../controllers/userController');
const router = express.Router();
router.route('/users/:username/decrementKluiten').put(userController.decrementKluiten);
router.route('/users/:username').get(userController.getUser);
router.route('/overview').get(userController.getOverview);
module.exports = router;
which makes sure the currency gets deducted. What I'm stuck on now is that, after all this has happened, I can't execute any code anymore after the fetch. I found though that I could execute code by resolving the promise in my route, but that feels really dirty and messes up my split up files:
router.route('/users/:username/decrementKluiten').put((req, res) => {
userController.decrementKluiten(req, res).then(x => {
console.log(x);
});
});
Is there a way to wait for my PUT to happen and still execute code after it did?
EDIT
userController.js
const {findChattersPerRole, getUserByUsername, decrementKluiten} = require('../actions');
const find = require(`lodash/find`);
const fetch = require(`isomorphic-fetch`);
const parseJSON = response => response.json();
module.exports = {
getUser: (req, res) => {
const username = req.params.username;
findChattersPerRole()
.then(chattersPerRole => {
const wantedUser = find(chattersPerRole, { username });
getUserByUsername(wantedUser.username)
.then(foundUser => {
if (foundUser) {
res.send(foundUser);
} else {
res.send(`No user has been found`);
}
});
});
},
getOverview: (req, res) => {
fetch(`https://tmi.twitch.tv/group/user/instak/chatters`)
.then(parseJSON)
.then(r => {
return res.json(r);
}).catch(err => {
console.log(err);
});
},
decrementKluiten: (req, res) => {
decrementKluiten(req.params.username, req.body.requiredKluiten);
}
}
actions.js
(Because this contains a lot of code I try to only include the relevant parts for this post, the database calls are done using Sequelize.js)
const decrementKluiten = (username, requiredKluiten) => {
return global.db.Viewer.findOne({
where: { username }
}).then(user => {
return user.decrement({ instakluiten: requiredKluiten });
});
};
module.exports = {
decrementKluiten
};

The issue is likely that you don't respond to the HTTP request in your /users/:username/decrementKluiten route. To solve this, change the exported decrementKluiten method in userController.js-file to this:
decrementKluiten: (req, res) => {
decrementKluiten(req.params.username, req.body.requiredKluiten)
.then(() => res.sendStatus(200))
.catch(() => res.sendStatus(500));
}
Some unrelated pointers to make your code a bit more readable, since you already use async functions in some parts of your code, but in other parts you interface directly with Promises.
The exported part of userController.js could utilize async functions:
module.exports = {
getUser: async (req, res) => {
try {
const username = req.params.username;
let chattersPerRole = await findChattersPerRole();
let wantedUser = find(chattersPerRole, { username });
let foundUser = await getUserByUsername(watnerUser.username);
if (foundUser) {
res.status(200).send(foundUser);
} else {
res.status(404).send('No user has been found');
}
} catch (e) {
res.sendStatus(500);
}
},
getOverview: async (req, res) => {
try {
let r = (await fetch('https://tmi.twitch.tv/group/user/instak/chatters')).json();
res.json(r);
} catch (e) {
res.sendStatus(500);
}
},
decrementKluiten: async (req, res) => {
try {
await decrementKluiten(req.params.username, req.body.requiredKluiten);
res.sendStatus(200);
} catch (e) {
res.sendStatus(500);
}
}
}
I've also added error handling in case something goes wrong, the server responds with a 500 Internal Server Error status code.
Judging by these lines in your TwitchAPI class:
const rawFoundUser = await fetch(`http://localhost:${PORT}/api/users/${userstate.username}`);
const foundUser = await rawFoundUser.json();
I assume you've tried to do const foundUser = await fetch('...').json(). This results in an error, but you can call the retuned value's methods and properties on the same line if you wrap the await expression in parentheses, like this:
const foundUser = await (await fetch('...')).json()`
If its methods does not return a Promise (i.e being synchronous), or you want to access a property, you can do:
const something = (await doSomethingAsync()).someMethod()
const somethingElse = (await doSomethingAsync()).property
I also noticed you're using template literals (backticks, `) for most strings without doing any template interpolation, which could simply be replaced with ' (single-quotes) or " (double-quotes).

How to make a function that can be called in other functions in Cloud Functions?

I have the following case, when deleting any data, I need to delete the app badges (at the moment I delete them using silent push notication and reduce the app badges number with the cloud function) if the user who sent the request has deleted. But since the user who deleted could send several requests to different users in different places, so I decided that I need to create a function that will be called in firebase database trigger functions and also it will help not to duplicate the same code everywhere .
The function will be approximate such
function adminRemoveAppBadge(userID, dataID, categoryID) {
};
And for example, call it in this function
module.exports = functions.database.ref('/cards/{cardID}/interestedUsers/{interestedUserID}').onWrite(event => {
const currentData = event.data.current;
const prevData = event.data.previous;
const cardID = event.params.cardID;
const interestedUserID = event.params.interestedUserID;
if (currentData.val() && !prevData.val()) {
// value created
return console.log('cardInterestedUserHandler - created');
} else if (!currentData.val() && prevData.val()) {
// value removed
console.log('cardInterestedUserHandler - removed', currentData.val());
const cardRef = admin.database().ref("cards").child(cardID);
const cardRefPromise = cardRef.once("value", function(snap, error) {
if (error) {
return error;
};
if (snap.val()) {
const cardJSON = snap.val();
const cardOwnerID = cardJSON["ownerID"];
if (cardOwnerID) {
const cardOwnerAppBadgesRef = admin.database().ref("userAppBadges").child(cardOwnerID).child("appBadgeModels").orderByChild("dataID").equalTo(cardID);
const cardOwnerAppBadgesRefPromise = cardOwnerAppBadgesRef.once("value", function (cardOwnerAppBadgesRefSnap, error) {
if (error) {
return error;
};
if (cardOwnerAppBadgesRefSnap.val()) {
var deletingPromises = [];
cardOwnerAppBadgesRefSnap.forEach(function(cardOwnerAppBadgesRefSnapChild) {
const appBadgeModelJSON = cardOwnerAppBadgesRefSnapChild.val();
const appBadgeModelID = appBadgeModelJSON["id"];
const senderID = appBadgeModelJSON["senderID"];
if (appBadgeModelID && senderID) {
if (senderID == interestedUserID) {
const cardOwnerAppBadgeRef = admin.database().ref("userAppBadges").child(cardOwnerID).child("appBadgeModels").child(cardOwnerAppBadgeModelID);
const cardOwnerAppBadgeRefPromise = cardOwnerAppBadgeRef.remove();
deletingPromises.push(cardOwnerAppBadgeRefPromise);
// to call
adminRemoveAppBadge
};
} else {
console.log("cardOwnerAppBadgeModelID == null");
};
});
return Promise.all(deletingPromises);
};
});
return Promise.all([cardOwnerAppBadgesRefPromise]);
} else {
return console.log("owner id == null");
};
};
});
return Promise.all([cardRefPromise]);
} else {
return console.log('cardInterestedUserHandler - updated');
};
});
Also functions are in different files. How can I call it in other firebase cloud functions and how do I deploy this function?
Update I tried to do so one of the options as written here and here, but when I tried to do deploy I got an error Cannot find module 'AppBadges/adminRemoveAppBadge.js'.
const functions = require('firebase-functions');
const admin = require('firebase-admin');
exports.adminRemoveAppBadge = function (userID, dataID, categoryID) {
console.log("adminRemoveAppBadge nil");
};
Requested this function so
var adminRemoveAppBadgeModule = require("AppBadges/adminRemoveAppBadge.js");
and call this functions so
adminRemoveAppBadgeModule.adminRemoveAppBadge(cardOwnerID, cardID, 0);

Google Functions are just JS - so normal routes to include code work.
I place my "library" functions in a folder /lib
So my functions folder looks like this:
/functions
/lib
BuildImage.js
SendEmail.js
index.js
package.json
...etc...
within my index.js I just include my code:
const SendMail = require('./lib/SendMail')
const sendMail = new SendMail({
database: db,
mailgun: mailgun
})
exports.sendContactUsMessage = functions.database.ref('/contact-messages/{itemId}').onWrite(sendMail.send(event))
EDIT Added /lib/SendMail.js code:
module.exports = class SendMail {
constructor(config) {
if (!config) {
throw new Error ('config is empty. Must pass database and mailgun settings')
}
if (!config.database) {
throw new Error('config.database is empty. Must pass config.database')
}
if (!config.mailgun) {
throw 'config.mailgun is empty. Must pass config.mailgun'
}
this.database = config.database
this.mailgun = config.mailgun
}
sendEmail (emailData) {
return new Promise((resolve, reject) => {
this.mailgun.messages().send(emailData, (error, body) => {
if (error) {
if (debug) {
console.log(error)
}
reject(error)
} else {
if (debug) {
console.log(body)
}
resolve(body)
}
})
})
}
...
}