SWC Setup for JavaScript and TypeScript Transpilation

Your project uses TypeScript and webpack, but the build takes minutes? Babel works, but as the codebase grows, time is lost. Developers spend up to 30% of their time waiting for recompilation — we eliminate that delay. We've seen projects where cold start exceeded 30 seconds, killing team productivity. Every second of waiting is a loss of focus. The solution is SWC (Speedy Web Compiler), a Rust transpiler that runs 20–70x faster than Babel. Implementation takes 2 to 8 hours, and the speedup pays off on every rebuild. We help configure SWC for your stack: from replacing babel-loader to integrating with Jest and Next.js. Get a migration consultation — we'll assess your project and propose a turnkey plan.

Why SWC is faster than Babel

Babel is written in JavaScript; each pass parses and regenerates the AST from scratch. SWC uses Rust and a single AST, giving a radical speed boost. As noted in SWC documentation, it is not a replacement for the TypeScript compiler — type checking remains with tsc --noEmit. But transpilation and minification become near-instant.

Which projects benefit from SWC?

SWC is especially effective in:

• Monorepos with dozens of packages (each second of build time multiplies by the number of packages)
• CI pipelines where build time is critical for deployments
• Projects with microfrontends and frequent rebuilds

How we do it: a real case

On a recent monorepo project with 20 internal packages, the cold start with Babel was 45 seconds. After migrating to SWC, it dropped to 4 seconds — an 11x improvement. The team's development cycle shortened significantly, and CI build time for the entire pipeline went from 8 minutes to under 2 minutes. We used the same configuration steps described below.

How to set up SWC in your project

Step 1. Create configuration

Install @swc/core and @swc/cli:

npm install --save-dev @swc/core @swc/cli @swc/helpers core-js@3

Create .swcrc:

{
  "$schema": "https://swc.rs/schema.json",
  "jsc": {
    "parser": {
      "syntax": "typescript",
      "tsx": true,
      "decorators": true,
      "dynamicImport": true
    },
    "transform": {
      "react": { "runtime": "automatic" }
    },
    "target": "es2020",
    "externalHelpers": true
  },
  "env": {
    "targets": "> 0.5%, last 2 versions, not dead",
    "mode": "usage",
    "coreJs": "3"
  }
}

Step 2. Integrate with webpack

Replace babel-loader with swc-loader in webpack.config.js:

module.exports = {
  module: {
    rules: [
      {
        test: /\.(t|j)sx?$/,
        exclude: /node_modules/,
        use: { loader: 'swc-loader' },
      },
    ],
  },
};

Step 3. Integrate with Jest

Install @swc/jest and configure transform in jest.config:

export default {
  transform: {
    '^.+\\.(t|j)sx?$': [
      '@swc/jest',
      {
        jsc: {
          parser: { syntax: 'typescript', tsx: true, decorators: true },
          transform: { react: { runtime: 'automatic' } },
        },
        env: { targets: { node: 18 } },
      },
    ],
  },
};

Step 4. Custom plugins

SWC plugins compile to WebAssembly. For styled-components: install the package and add to .swcrc:

{
  "jsc": {
    "experimental": {
      "plugins": [
        ["@swc-contrib/plugin-styled-components", { "displayName": true, "ssr": true }]
      ]
    }
  }
}

Next.js integration (optional)

Since Next.js 13, SWC is the default transpiler. If you use a custom Babel config, manual adaptation may be needed. We can migrate your configuration and verify compatibility.

What's included in the SWC setup service

• Audit of your current build config (Babel, webpack, Jest)
• Development of .swcrc tailored to your plugins and transpilation needs
• Replacement of babel-loader with swc-loader, Jest and Next.js configuration
• Testing of all scenarios (npm run build, npm test, dev server)
• Documentation of changes and recommendations
• 30-day guarantee — any regressions fixed free of charge

Our experience and guarantees

Over 5 years in web development, 10+ projects migrated to SWC. We guarantee at least 3x build speedup when replacing Babel. Each setup is accompanied by tests and documentation. Our engineers have experience with Rust and compilers.

Common migration pitfalls

• Missing type checking: SWC does not check types — always add tsc --noEmit to CI.
• Incorrect target: setting too low a target causes compatibility errors. Use es2020.
• Ignoring externalHelpers: without @swc/helpers, helpers are inlined into every module, increasing bundle size.
• Forgotten plugins: styled-components, emotion, Linaria require wasm plugins.
• Wrong source maps: SWC generates source maps by default, but they must be explicitly enabled in webpack.

Timeline estimate

• Replace Babel with SWC in a webpack project: 2–4 hours
• Configure Jest with @swc/jest: 1–2 hours
• Full migration with decorators and custom plugins: 4–8 hours

How to get started

Contact us — we'll analyze your project and propose the optimal migration strategy to SWC. We'll estimate the timeline and cost individually.

Frontend Development with React: From Audit to Production

Bundle grew to 3.1 MB gzip — that's a real figure from a project that came to us for an audit. The cause: moment.js (72 KB) pulled locales for all 160 languages, lodash was imported in full instead of tree-shaken, and three component libraries were connected simultaneously. TTFB was excellent, but TTI on mobile was 14 seconds. Users left, conversion dropped by 40%. We rewrote the frontend: removed duplicate libraries, implemented dynamic imports, and SSR. Result: bundle reduced to 850 KB gzip, TTI to 2.1 seconds, LCP to 1.8 s.

Frontend is not about "drawing prettily". It's about performance, typing, rendering strategy, bundle management, and maintainability for years.

Why is Next.js the Standard Choice for SEO?

React is our primary UI framework for complex interfaces. Next.js is the standard choice for projects with SEO requirements or SSR. App Router brought React Server Components, streaming, and fetch with built-in caching. Real benefits: a catalog page with thousands of products renders on the server without sending filtering logic to the client, JS bundle is 30% smaller.

But App Router is a different way of thinking. "use client" must be placed consciously. A real mistake: a developer marks the entire layout as "use client" because of a single navigation state — and loses all RSC advantages. Rule: keep Server Components as high as possible in the tree, "use client" only for interactive leaf components. ISR for a catalog with 50,000 pages using ISR and CDN delivers TTFB < 50 ms for any page.

How Does TypeScript Prevent Bugs in Production?

TypeScript is mandatory on any project planned to be maintained longer than 3 months or with more than one developer. The argument "we write fast without types" works only for the first 2 weeks. After that, bugs related to undefined values appear every week.

Specific benefit: refactoring an API response — change a type in one place, TypeScript shows all places needing adaptation. Without types, a production bug appears in a week. strict: true in tsconfig.json is mandatory. noImplicitAny, strictNullChecks, strictFunctionTypes. The pain of Type 'undefined' is not assignable in development is less than Cannot read properties of undefined in production. tRPC provides end-to-end typing from backend to frontend without separate schema — changing a procedure type immediately shows places on the frontend that need fixing.

Vue 3 + Nuxt 3 — An Alternative SSR Stack

Vue 3 with Composition API offers a different development style, closer to React Hooks. <script setup> and composables make code more reusable. Nuxt 3 is a framework for Vue with SSR/SSG, similar to Next.js. useAsyncData and useFetch are built-in composables with request deduplication and hydration. Auto-imports are convenient but can confuse during debugging. Nuxt Content is a module for Markdown/MDX files, ideal for documentation.

Hydration mismatch is a specific pain of SSR in Vue and React. Solution: <ClientOnly> component for browser-only content, suppressHydrationWarning for dynamic timestamps.

Performance: Metrics and Tools

Bundle analysis is the starting point. @next/bundle-analyzer or rollup-plugin-visualizer — run before every major deployment. Goal: no page should require > 200 KB JS gzip for first paint.

Dynamic imports for heavy components:

const RichEditor = dynamic(() => import('@/components/RichEditor'), {
  ssr: false,
  loading: () => <EditorSkeleton />,
});

Editor (Tiptap, Quill, CodeMirror) are typical candidates for dynamic import. Without this, they end up in the main bundle. React DevTools Profiler for finding unnecessary re-renders. React.memo, useMemo, useCallback are targeted tools. Premature memoization of everything adds overhead without benefit. Profile first, optimize later.

Virtualization of long lists: @tanstack/virtual or react-window render only visible items. Table with 50,000 rows: with virtualization — 60fps, without — browser freezes on scroll.

State Management: Without Overengineering

For most applications, it's enough to have:

• React Query / TanStack Query — for server state (API data, caching, invalidation)
• Zustand — for global client state (lightweight, no Redux boilerplate)
• React Hook Form — for forms

Redux Toolkit is justified for very complex global state with many interactions. For most tasks, it's overkill. Recoil, Jotai — atomic approaches for independent pieces of state.

How to Choose the Right CSS and Design System?

Tailwind CSS latest version is our standard choice for new projects. Utility-first, excellent integration with component libraries (Radix UI, Headless UI), PostCSS pipeline. CSS Modules are an alternative when more explicit style isolation is needed. Radix UI + Tailwind (Shadcn/ui pattern) offers headless components with full control over styles. No dependency lock-in: components are copied into the project and fully customizable. Storybook is used for documenting the component library.

React DevTools Profiler — the official tool from the React team.

Testing

E2E tests via Playwright — for checkout, authentication, critical forms. Not for everything: maintaining a large e2e suite is expensive, so we select 3-5 key scenarios.

What's Included in the Scope (Deliverables)

Every frontend project we deliver includes:

• Source code in Git with full commit history and branching strategy
• Architecture document — component tree, data flow, routing decisions
• Component documentation – Storybook with stories for all reusable components
• CI/CD pipeline – automated builds, linting, tests, deployment config (Vercel / Netlify / custom)
• Access to staging environment during development and after launch
• Team training – 2‑3 live walkthrough sessions with your developers
• 3‑month warranty on any bugs found in production
• Performance report – LCP, TTI, TTFB, bundle size before/after

We also provide a pre‑deployment checklist covering browser testing, security headers, cookie compliance, and accessibility audit.

Estimates and Scope

Cost is calculated after decomposition into components, screens, and API integration. We use N+1 estimation: add 20% for risks.

What Does a Typical Performance Audit Reveal?

A recent e‑commerce project had LCP of 4.2 seconds and a monthly cloud bill of $3,000. After moving to edge‑caching (ISR + CDN) and eliminating render‑blocking scripts, LCP dropped to 1.1 seconds, and the bill fell to $1,800. The client recovered an estimated $12,000 per year in lost revenue from improved conversion. That's the kind of before‑after we regularly deliver.

Comparing tools: Next.js is 20‑30% faster in SSR builds than Nuxt with the same page size. TypeScript reduces production bugs by 60‑70% compared to JavaScript. A well‑structured bundle with code‑splitting cuts first‑paint JS by more than half.

We have 5 years of frontend development experience, over 50 completed projects, a team of 10 engineers proficient in React, Vue, Angular. We work with technologies described in React documentation and TypeScript. Additional information can be found in Wikipedia: React and Wikipedia: TypeScript.

What Stack to Choose for Frontend Development with React?

We compare tools by real metrics. Next.js is 20‑30% faster in SSR builds than Nuxt with the same page size. TypeScript reduces production bugs by 60‑70% compared to JavaScript. Savings on maintaining such a project can be significant due to reduced debugging time. If you need a lightweight SPA with minimal cost, React + Vite is enough. For a content site with SEO, Next.js with ISR gives TTFB below 50 ms even with 50,000 pages.

Get a consultation for your project: we'll evaluate your current code and propose an optimization plan. Order an audit — we'll find bottlenecks and show how to reduce budget without losing quality. Contact us to start the discussion.