20 ways to become a better Node.js developer in 2020

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Don’t be that ‘screwdriver guy’, enrich your toolbox, diversify yourself

Short Intro

My name is Yoni Goldberg, I’m an independent Node.js consultant, the co-author of Node.js best practices, and JavaScript testing best practices. I work with customers in US & Europe on planning, testing and hardening their apps.

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📗 Want to take your testing skills to the extreme? Consider visiting my comprehensive course ‘Testing Node.js & JavaScript From A To Z’

Reviewed & improved by Bruno Scheufler

1. Use TypeScript features thoughtfully


  • Type Inference can help in reducing TypeScript verbosity and make it look more like vanilla JavaScript
  • Type aliases are an alternative simple and leaner way for defining constructs (comparing with interfaces).
  • Using TypeScript for encapsulation? access modifiers are coming soon to vanilla JS

2. Modernize your testing toolbox. Ava & Jest are changing the game

  1. Speed — modern test runners are faster thanks to the multi-process execution model. They also apply advanced optimizations like learning tests stats over time and prioritizing slow tests to run first. This is not only about test runners, but other tools also boost test speed: fake in-memory database allow testing with DB without the involvement of IO, some npm packages offer a local and in-memory version of popular cloud services. To name a few examples.
  2. Outstanding developer experience — modern test runners and tools are designed to accompany the coding experience and provide valuable insights. For example, should a test fail, Jest and Ava will not just report a failure rather extract the related code from the unit under test. Thanks to this, developers get much richer context which leads to a faster resolution

Some of the traditional tools were designed for CI or for occasional test execution. In times where teams deploy once a day, discovering a bug after 4 hours is not good enough. Modern tooling allows running tests, including component tests with DB, constantly even during coding. This approach allows for testing more layers and more use cases earlier and it’s called ‘shift left’ — read more about it below


  • AVA & Jest are the new sophisticated kids in town
  • mongodb-memory server is amazing for testing with MongoDB server — it installs, instantiates and configures a local and real Mongo with in-memory engine
  • Cypress makes E2E testing, including backend’s API related tests, a delightful experience
  • aws-sdk-mock fakes many AWS services

3. Plan your ES6 modules usage strategy. See, it’s a bit tricky

Given all of these considerations, what’s your strategy: jump straight into the ESM water and work around the issues? or use ESM with babel/TS as a safety net? maybe keep on with gold old common js ‘require’ but avoid incompatible syntax like usage of __filename, __dirname, JSON resolution, and others? there are no strict answers here but at least we strive to ask the right questions

Thanks to Gil Tayar for these great insights


4. Meet the latest JavaScript features that are turning green soon


  • Private methods and fields are at stage 3 (active proposals) so if you’re opting for TypeScript only for encapsulation — now there is one more option to choose from
  • Nullish coalescing (stage 4) will finally put a stop to our nasty habit of checking for nulls & undefined using the !variableName syntax (which also includes zero and therefore is error-prone)
  • Promise.any is the latest edition to the promise.{something} family, unlike all the others (promise.all, promise.settleAll, promise.race) it will abort should any Promise resolve or reject. This is one of the final nails in the coffin of Promises helper libraries like ‘async’ and ‘BlueBird’

5. Experiment architectures outside of your comfort zone. Note how GraphQL is disrupting the traditional models

Ensure you’re familiar with layered architectures like n-tiers, DDD, Hexagonal/Onion/Clean. They look very different but their primary principle is smilar — isolating the domain (i.e. core data schema and business logic) from the surrounding tech (e.g. APIs, DB). Introduce yourself also to streaming style architectures which see a great increase in popularity. Then, spend some time with data-driven architectures that are best implemented nowadays with GraphQL frameworks.

Speaking of GraphQL, it’s interesting how some of its flavors disrupt the traditional separation between API and data-access layers, instead of repeating similar code and schemas twice these frameworks allow to declaratively define the entire app with one schema. This approach will greatly boost the go-to-market for data-driven apps which are not likely to embed complex logic.


6. Check out the winner of the 2019 oscar — Nest.js

Unlike Express & co., Nest.js brings a full-fledged, batteries-included, framework (e.g. handles the data access layer, validation, etc). Its design style is highly ‘inspired’ by Angular — opinionated, TypeScript-based and embodies heavy modularization constructs. That said, it still offers great flexibility in choosing it’s sub-frameworks. Given all these goodies, I have no single doubt that teams doing their first steps with Node.js will move way faster with Nest.js rather with minimalist Express approach.

With all it’s greatness, it’s not flawless. One may doubt, is the heavy modularized Angular approach that was designed to ease the pain of huge frontend codebase suits the backend needs? aren’t we jumping too far from minimal Express to a huge and such an opinionated framework? are all of these heavy modularity features needed in a world of small Microservices? or the equivalent, isn’t it promoting monoliths (“I can easily handle 30,000 LOC in my code base”)?

At least we now have an option to choose from.


7. Apply gradual deployment techniques like feature-flagging, canary or traffic shadowing

What are these techniques? Canary is the most well-known and simple. It tunes the routing so the next version is deployed and served to a group of users, starting from users are more likely to tolerate bugs (e.g. office employee, non-paying customers) and as the confidence grows it serves to more and more users. This might sound complex, but frameworks such as istio for K8S and AWS serverless handle most of the heavy lifting work. The next technique, feature flagging, is more powerful but also demands to get your hand dirty. It basically suggests wrapping a feature code with condition criteria that tell which users should benefit this new feature. Usually, it also comes with a dashboard for product managers to turn on and off features. This allows non-technical users to be part of the party and also support finer-grained advanced criteria. For example, using flags you may activate some experimental feature only for users from a specific city, on a specific machine instance that has a specific browser. One last super-interesting technique to look for is traffic shadowing which I’ll leave you to read about.

The value of these techniques is immense: unlike code-testing which demands great effort all the time, tuning your routers for canary deployment only happens once(!) and it also ‘test’ you code under realistic production environment. Learn about this fascinating world and plumb one of this technique into your pipeline


8. Shift your testing left — test more things and sooner

Test more things sooner, discover bugs early. How can we translate this idea into tangible development tasks? run a diversified set of tests as part of every commit and even during coding: component/api tests with real (in-memory?) DB just like you run unit tests, tests with realistic production input using dedicated property-based libraries, apply security scanners, run performance load tests and more. See below a list with dozens of tests one can run across the pipeline


  • Fast-check npm package for property-based testing allows invoking your units/API with many input permutations
  • Check our framework and tools for scanning docker containers for CVEs like snyk, Trivy, Quay
  • Tuning your real DB for in-memory operation without IO will make it practical to run api/component tests instantly almost like unit tests: this is how you would tune PostgreSQL (here is a ready-to-use dockerized version), mongodb-memory server will install and configure a local and real Mongo with in-memory engine.

9. Shift your testing right — test in/with production

So should we shift left or right? both. A modern approach for software delivery is not just thinking about tests rather about a pipeline. Given that many phases exist until the next version is served to the user — planning, development, deployment, release — each one is another opportunity to realize issues, stop, or build accumulating confidence. Code testing is a significant step on the pipeline, but plugging other tests into the pipeline will provide more confidence.


10. Be ready to use your new async pocket knife — worker threads

Now for some bad news — worker threads are not a lightweight thread that one spawn in no-time on demand. They actually duplicate the entire engine so it can become quite slow until they start running CPU-bounded requests will suffer additional delay. For this reason, consider a thread-pool (link below)


11. Deepen your Docker and Kubernetes understanding. It highly affects your Node.js code.

Few examples: it’s a well-known practice to ensure all outgoing requests are being replayed upon failures (the circuit breaker pattern), this can be done both on the infrastructure level using K8S Istio, or at the code itself using dedicated packages. Which one would you prefer and why? interesting choice, isn’t it? Let’s discuss other scenarios — K8S might kill and relocate pods, when it sends a kill signal the webserver might handle 2000 users. When a pod just crashes, they will quickly become angry 2000 users unless you implement a graceful and thoughtful shutdown. What is the grace period? well, this requires some Kubernetes learning, right? Sometimes the kill signals from K8S won’t even reach to your code if you use ‘npm start’ command, why? this requires some understanding of how Docker processes and signals are managed (the 1st link below will answer this question). One other interesting challenge is settling two contradicting things — how can test tools run within Docker containers during the pipeline but then removed before production? One last interesting example is configuring the allowed memory per container, given that v8 recently stopped limiting the heap size which will now keep growing as needed, this might interfere with K8S resource limits (common best practice) — make a decision and align the Node.js side with the K8S side

all of these challenges call you to dig deeper into the fascinating world of Docker clusters (or Serverless if you wish)


12. Security: Learn to think like an attacker by skimming through vulnerable code examples


  • NodeGoat is a project that intentionally embodies security weaknesses for educational purposes. Don’t miss this doc page with attack examples
  • Read my list of Node.js Security best practices which contain 23+ attack ideas including JavaScript code examples
  • Conduct a monthly threats analysis meeting where the team tries to look at the application design and propose attacks. sound boring? not necessarily if you add some gamification and reward members that find an exploit, or run a competition between a blue team that designs a module vs the read team which tries to find exploits

13. Learn at least one: ELK or Prometheus

Ops folks know nothing about the event loop and how to monitor it (npm package does this), only you can propose and implement this important metric. Only developers can suggest the right V8 monitoring limits alerts. Developers might even write automated tests to ensure that when application errors are thrown — the right metrics are incremented. One another valuable activity is custom applicative metrics — coding some measurement of user activities can be very efficient in tracking production anomalies. Consider an e-commerce app, if the number of purchases is tracked and it suddenly drops dramatically in production — this is likely to imply some underlying issue


14. Use machine learning as a black-box product

Obviously, better delve into the details and read the manuals. In no way, I’m suggesting a careless use of technologies. What I do propose however is that becoming familiar with the high-levels is better than knowing nothing and can build the motivation to keep exploring. Should I used ML taxonomy wrong above — please understand, I’ve just started my ML journey


  • ml.js — a swiss army knife of machine learning tools
  • Brain.js specializes in neural networks, has great docs and a free video course
  • Natural brings the world of NLP into Node land: text comparison and similarities, sentiment analysis, text classification and more

15. Sleep >7 hours a night. This matters far more than any technology you use and scientifically prooved to make you a better developer

your sleep quality and stress level matter far, far more than the languages you use or the practices you follow. Nothing else comes close: not type systems, not TDD, not formal methods, not ANYTHING.

It’s packed with examples and researches — I urge you to visit there and dig into those pearls of wisdom


16. Quit Express, it’s aged and not maintained properly. Fastify and Koa are great candidates in 2020

The last commit to the Express project was pushed somewhere 6 months ago… Since then Fastify & Koa saw dozens of builds and they keep improving. It’s frankly not appropriate for the Node.js ecosystem to rely heavily on a library that doesn’t keep in step with the times.

That said, most of the community tools and docs rely on Express. I hope to see community leaders, course makers, bloggers creating more content on its modern alternatives.


17. Revisit these bullets from last year — some are still highly relevant


  • Bullet number #4 — “Plan how to utilize Async-Hooks to reach better tracing and context”
  • Bullet number #11 — “Have a package update strategy. A lesson learned in 2018: updating too soon is a dangerous practice”
  • Bullet number #17 — “Deepen your Linux OS understanding, focus on the anatomy of a Linux process”
  • Bullet number #18 — “Dive deeper into the Node.js internals”

18. Enrich your CI with automated quality tools


  • Scan Docker containers for CVEs using tools like snyk, Trivy, Quay
  • lockfile-lint will detect attempts to inject malicious dependencies using the npm lock file (e.g. edit a dependency URL within the lockfile)
  • swagger-express-validator will ensure that your routes conform to the swagger schema
  • eslint-plugin-import is an outstanding linter that performs dozens of checks on module and dependencies resolution. For example, it can warn when import/require is not at the beginning, disallow mutable exports with var or let, discoverextraneous packages that aren't declared with package.json and much more
  • commitlint will enforce semantic commits which then can lead to automatic semantic versioning of Microservice and packages
  • dependency-cruiser is a CLI tool that allows declaring flexible policies on allowed and disallowed dependencies. Using this you can craft custom rules like what licenses are allowed, allowed paths and more

19. Enrich your mindset, diversify your toolbox

These are false-dichotomies — it’s not a binary question, all these paradigms embody many different ideas, and still, we tend to pick all or ignore all. For example, Functional Programming currying and monads feel weird? that’s fair, consider other more mainstream FP ideas like pure functions. Ignoring TypeScript because OOP is not your style? maybe use only its type system and stick to vanilla JS objects and functions. Cherry-pick ideas and features, not a package.

How exactly do I plan to diversify my stack in 2020? I’ll probably use Fastify for the web layer, with a mix of REST and GraphQL. The data access layer will constitute some lightweight ‘ORM’ but only for migrations and connection pooling (no dichotomy, I’m picking the right ORM features for me). As for the DB, I plan to use a relational DB mixed with JSON columns. My coding style is based on simple and flat vanilla JavaScript objects — but I usually mix it with some classes when appropriate and keep most of my functions pure. The overall architecture style will be centered around Microservices but maybe in a monorepo — I’m not obliged to pick all the Microservice bells and whistles, right?. As of testing, I definitely want to run TDD-style iterations of refactoring for my code, but not necessarily code the tests first — I pick the TDD features that suit my style. What type of testing? mostly component tests (i.e. api) but mix this with unit testing to cover parts with heavy logic.

By no mean, I suggest that this is the best stack. It is, however, a diversified stack that mixes and matches multiple ideas from many paradigms. Obviously assemble your own stack, just don’t be afraid of tiptoeing into unexplored territory and get inspiration from many sources of wisdom.

p.s. I’m not advocating for becoming a jack of too many trades. Actually mastering some technologies is important. My point is being pragmatic and open to great ideas. Don’t be “that screwdriver guy”, enrich your mindset, diversify your toolbox

20. Get inspiration from these great 5 starter projects


  • node-api-boilerplate is a great showcase for DDD with an application layer that demonstrates organizing code by feature
  • dev-mastery comments-api is an excellent translation of clean architecture to Node.js and it comes with this super explainer video
  • Typescript-starter won’t teach you any architecture concepts but a nice showcase for TypeScript set up with modern libraries and great docs
  • nodejs-api-starter is the starter for those who seek a real-world GraphQL implementation including errors and auth
  • bulletproof-nodejs is a well-known starter that uses the 3-tier folder structure which is my personal and recommended way of structuring a Node.js app

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Software Architect, Node.JS Specialist. Consultant, blogger, conference speaker, open source contributor — author of the largest Node.js best practices guide

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