Using TypeScript with Bundlers

Bundlers follow module imports and produce assets for browsers, often rewriting imports, tree-shaking unused code, and optimizing output. TypeScript may be type-checked separately because fast transpilation is not always full type checking. Match moduleResolution to the bundler and run tsc --noEmit in CI for type safety.

This module's public function is straightforward for a bundler to include. In a web project the bundler analyzes imports and assets, while tsc --noEmit can inspect the same source's static types.

A bundler building successfully does not prove it ran full TypeScript type checking.

Save as using-bundlers.ts. The following program passed strict TypeScript compilation, and the displayed output was captured by executing its emitted JavaScript with Node.js 22.16.0.

TypeScript source

export function total(values: number[]): number { return values.reduce((a, b) => a + b, 0); }
console.log(total([2, 4, 6]));

Verified output

12

Compile: npx tsc --strict --target es2022 --module commonjs using-bundlers.ts; run: node using-bundlers.js. For Node.js API examples, install @types/node first. For browser projects, use the browser-specific instructions below.

The example demonstrates the code-level behavior; the related configuration or test commands are shown separately when needed.

This module's public function is straightforward for a bundler to include. In a web project the bundler analyzes imports and assets, while tsc --noEmit can inspect the same source's static types.

Predict what changes if you alter one input. Then run the code to compare your reasoning with the real output.

Practical project lab: These are real configuration and source-file examples, not a TypeScript object that merely describes settings. Place the files at the named paths relative to one project directory.

index.html

<div id="app"></div><script type="module" src="/src/main.ts"></script>

src/main.ts

const app = document.querySelector<HTMLDivElement>("#app");
if (app) app.textContent = "Bundled TypeScript";

tsconfig.json

{"compilerOptions":{"target":"ES2022","module":"ESNext","moduleResolution":"Bundler","strict":true,"noEmit":true,"lib":["ES2022","DOM"]},"include":["src"]}

Commands

npm create vite@latest my-app -- --template vanilla-ts
npm run build
npx tsc --noEmit

Use a real bundler project for runtime asset handling; do not run this browser file in Node.

This project requires its named external tool or dependency and was supplied as setup guidance; it was not claimed as an executed test here.

A bundler building successfully does not prove it ran full TypeScript type checking.

Identify whether the failure is a type-checking issue, a configuration issue, or a runtime behavior issue before choosing a fix.

Create an HTML entry and import this function in a Vite project. Run a separate tsc --noEmit check.

Write down your expected result first. For configuration examples, compare compiler output and diagnostics; for test examples, make the assertion fail deliberately to verify that the tool reports it.

For the exact current options and platform behavior, consult the official documentation. These examples were verified using the tool versions described above.

Bundlers follow module imports and produce assets for browsers, often rewriting imports, tree-shaking unused code, and optimizing output.

Run the primary example, then complete the practice task or environment-specific lab.