TypeScript
Types that deliver
React
UI that converts
Next.js
App Router, seriously
Angular
Enterprise, modern
Nuxt
Vue, full stack
NestJS
APIs with boundary protection
Vue
Precise UIs
Node.js
Runtime with responsibility
Remix
Web fundamentals first
Medusa.js
Composable Commerce
StrapiContent APIs with control
DirectusSQL data as secure APIs
Payload CMSNext.js backend in TypeScript
Encore.tsAPIs and infrastructure as code
Shopify HydrogenShopify storefronts built with React.
VendureHeadless Commerce for B2B
HTMX
HTML that works
JavaScript
Edge language
Alpine.js
Interaction without bloat
Vanilla JS
Framework-free, full control
React Native
Mobile, one team
PostgreSQL
Data that lasts
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Pipelines that deliver
GitLab
Repo, CI, releases
Dedicated Resource · JavaScript
Before frameworks, there is JavaScript. A dedicated JavaScript developer from Typescriptaz masters the language itself: the event loop, modules, and patterns that remain readable five years from now. We rescue legacy code, write tooling, and keep teams proficient in the language that actually runs in the browser.
Use
In many companies business-critical logic is embedded in years-old JavaScript: jQuery plugins, custom build scripts, global variables. Your JavaScript developer modernizes that code without endangering the business—using tests up front, ES modules instead of global chaos, and a build everyone on the team understands.
This also includes tooling: linting, formatting, bundling, and scripts that save your team time every day. And when the code is stable, the next step often leads to TypeScript – stepwise and without downtime.
For decision-makers, legacy JavaScript is often a silent risk: it works until it doesn't—and then nobody knows why. A dedicated person makes that code understandable, testable, and secure before it becomes an emergency.
Typical mandates: Platform teams, legacy modernization, shared libraries.
Tools: Modern ECMAScript, Node.js, Vite, Vitest, Playwright
Book directly
$12,500 / month
150 hours, directly employed and dedicated solely to your backlog. At kickoff, you meet the person before work begins.
Quick explanation
JavaScript is the web's programming language: it runs in every browser and, with Node.js, on servers. The language is updated annually in the ECMAScript standard and has changed a lot in recent years—with modules, classes, async functions, and many new standard features. Many companies therefore have two worlds side by side: modern code and legacy code from the jQuery era. An experienced developer brings both together and creates a common, future-proof foundation.
Expertise
Seniority isn’t shown on the resume but in code review. Our team looks for it with JavaScript.
01
Closures, prototypes, async flows, modules: A senior JavaScript developer understands what’s happening under the hood. That’s a prerequisite for safely changing legacy code and finding bugs that are invisible on the surface.
02
Characterization tests record how existing code behaves today—even if no one exactly knows why. With this safety net, modernization becomes predictable.
03
Vite, ES modules, modern linters, and formatters replace accumulated build scripts. An experienced developer handles the migration without breaking deployments or existing integrations.
04
XSS, unsafe inclusion of third‑party scripts, missing Content Security Policy: such vulnerabilities often live in older code. A senior developer finds and fixes them systematically.
05
Promises, async/await, and event-driven flows are a common source of bugs in mature codebases. A senior finds race conditions and unhandled errors and makes flows robust.
06
Long tasks, layout shifts, and unnecessary DOM operations slow pages down. Using the browser DevTools and clear budgets, performance becomes measurable and can be improved deliberately.
Typical situations
01
And nobody dares touch it anymore? We lock down behavior with tests and replace old plugins step by step with modern JavaScript.
02
Outdated Webpack setup, Gulp tasks nobody understands? We build a lean toolchain with Vite—faster and documented.
03
Outdated packages, unsafe DOM manipulation, missing Content Security Policy: we find and close the gaps—prioritized by risk.
Risk under control
Evolved frontend code is rarely documented and often business-critical. We address these three risks specifically:
If only one person still understands the old code, every absence is a risk. We document behavior and dependencies and spread knowledge across the team—through code reviews and short handoffs.
Even small changes in established code can have unexpected consequences. That's why we run tests first, then apply changes in small steps that can be rolled back individually.
Outdated jQuery versions and plugins contain known vulnerabilities. We inventory all libraries, prioritize by risk, and replace the most critical first.
Tracking, chat widgets, and advertising scripts run with full privileges on your pages. We inventory all third‑party scripts, assess their risk, and apply protections such as Content Security Policy and Subresource Integrity.
Transparency
Business case
A dedicated JavaScript developer pays off primarily through risk reduction. Outdated code with known vulnerabilities can cause data breaches and outages that are far more expensive than modernization. Tested, understandable code lowers the cost of every change. And a modern toolchain accelerates builds and deployments — every day, for the whole team.
The first two weeks
Analysis, first delivery, clear plan. Read about how we work in general at How we work.
01
Which libraries, which build steps, which dependencies? We document what's there—including what no one remembers anymore.
02
Initial tests for critical flows are created so changes can be made immediately with confidence.
03
You receive a plan identifying which parts to modernize first and when switching to TypeScript makes sense.
After kickoff
How a typical engagement develops after the first two weeks—aligned with your backlog.
01
Inventory of all libraries and build steps, initial tests for critical processes, and a prioritized risk list.
02
The most critical libraries are replaced, the build is modernized, and known security vulnerabilities are closed.
03
Modern, tested code in the most important areas, a documented toolchain, and a plan for migrating to TypeScript.
Example scenario
A travel provider uses years‑old code for its booking process, spread across jQuery plugins and custom scripts. Changes take a long time and no one trusts the price calculation. A dedicated JavaScript developer first captures the behavior with tests.
Afterwards, plugins are replaced one by one with modern code, the build moves to Vite, and known security vulnerabilities are closed. The booking process continues without interruption.
For the company, this means: price and offer changes go live quickly again, security audits run without critical findings, and knowledge is no longer confined to a single person.
Collaboration
Modernization can be planned in stages: an hour bundle covers the first clearly defined steps. If this becomes a longer rebuild phase or ongoing development is added, a dedicated developer on a monthly plan is the more economical choice.
The discovery package with code review is suitable for assessing the state of your code and the realistic effort required.
All rates, pools, and effective prices are detailed in the Pricing table.
Straight talk
Not every legacy codebase needs modernization. If an application runs stably, is rarely changed, and has no known security vulnerabilities, monitoring can be the more economical choice. We therefore prioritize by risk and benefit and propose refactors only where they pay off. A full rebuild is rarely the best answer—incremental modernization usually delivers value faster.
For IT decision-makers
Can the person safely modify code without tests—and how would they proceed?
What experience does she have with replacing jQuery?
How do you assess security risks in third-party scripts?
Can they modernize an existing build pipeline without endangering deployments?
Do they document their findings for your team?
Glossary
The language’s standardized module system uses import and export.
A test that captures current code behavior before it is changed.
A security policy that specifies which scripts and sources a page may load.
Splitting delivered code into smaller bundles that are loaded only when needed.
Frequently asked questions
Rarely. Often it's more sensible to stabilize existing JavaScript code first and then add types file by file. That keeps the product continuously deliverable.
With a safety net of end-to-end tests and a stepwise approach, much of what used to require jQuery can now be done natively by the browser — making the migration easier than you might think.
Yes—part of the mandate. Your JavaScript developer reviews pull requests, shares patterns, and helps the team keep quality consistently high.
The ones your users actually use. We define target browsers together, usually based on your analytics data, and align build and tests accordingly.
For many tasks, yes—the language is the same. For larger backend concerns like scaling and operations, we recommend a specialized role.
That depends on the scope and condition of the code. After the inventory in the first two weeks, you'll receive a plan with stages that each deliver independent value.
Not mandatory. The important thing is a current version without known security vulnerabilities. Where jQuery now only serves a few purposes, replacing it with native browser features is worthwhile.
We read, test, and document. Characterization tests capture behavior; short notes in the repo explain relationships. Gradually this yields documentation your team can maintain.
Typically ESLint or Biome, Prettier, and automated tests in CI. We align the rules with your team so they help in daily work instead of slowing you down.
Yes. Alongside modernization, we handle ongoing adjustments, bug fixes, and security updates—so operations remain stable while the codebase improves step by step.
With clear conventions, automated CI checks, and code reviews, we evaluate new dependencies before they enter the project, and we document decisions in the repo.
Not necessarily. Many steps can be handled during an ongoing engagement alongside new features. For larger refactors, we recommend a separate hour bundle so the effort remains transparent.
Bottom line
A dedicated JavaScript developer turns evolved code into a secure, understandable foundation. You close known security gaps, distribute knowledge across the team, and establish the basis for a later migration to TypeScript — step by step and without downtime.
Next step
Tell us the stack, scope, and start window. We usually respond within one business day—with a specific person instead of a stack of profiles.
Quick contact
TypeScript resources from Austria and Germany, permanently employed with us. Tell us the stack, scope, and desired start date. We typically respond the same business day — with availability, appropriate seniority, and a concrete start window.
US & European billing
Choose the contracting entity that fits your procurement process. Engagements can be contracted and invoiced through our European locations or through Anexia Inc.152 W. 57th Street, 7th Floor, New York, NY 10019, USA. Talk to us about billing.