TypeScript Single-File Bundler That Preserves Types

[hariria]

TypeScript Single-File Bundler That Preserves Types

Referencing

• Bundle typescript without transpiling rollup/rollup#2824
• TypeScript Single-File Bundler dsherret/ts-morph#1629

I'm looking for a tool that can bundle multiple TypeScript files into a single TypeScript file while properly handling type imports. I wanted to check if anyone has already created something similar with the new typescript compiler.

Use Case

Take multiple TypeScript files that import from each other and external packages, then generate a single TypeScript file that works standalone with all dependencies inlined.

Example Input

// subtract.ts
export function subtract(a: number, b: number) {
  return a - b;
}

// add.ts (entry file)
import { subtract } from './subtract'
import type { GlobTask } from 'globby'

export function add(a: number, b: number) {
  return a + b;
}

Expected Output

A single TypeScript file that contains:

1. The contents of both files
2. Only the necessary type definitions from external packages (like the GlobTask type from globby)
3. Preserves the original exports

Key Requirements

• Must handle both local imports and external package imports
• Must properly handle type-only imports (import type)
• Should intelligently exclude Node.js built-in modules
• Ideally allows configuring which packages should be kept external vs bundled
• Provide customizability where needed

I was hoping the new typescript compiler might be a great tool to accomplish something like this. Has anyone built something like this or have suggestions for how to approach it?