Bundle code with Deno.bundle

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Deno.bundle compiles a module graph into a single JavaScript file, resolving and inlining all imports, including jsr: and npm: packages. It is the programmatic counterpart of the deno bundle subcommand, useful in build scripts that need to produce self-contained output for browsers, serverless platforms, or distribution.

Write a small entrypoint to bundle. It pulls a helper from the standard library on JSR, so the bundler has a real dependency to resolve.

await Deno.writeTextFile(
  "app.ts",
  `import { toCamelCase } from "jsr:@std/text";
console.log(toCamelCase("hello from the bundle"));
`,
);

Bundle the entrypoint. The platform option targets either "deno" or "browser", and write makes the bundler save the file itself. Without outputPath the bundled code is returned in result.outputFiles instead.

const result = await Deno.bundle({
  entrypoints: ["./app.ts"],
  outputPath: "dist/app.js",
  platform: "deno",
  minify: true,
  write: true,
});

The result reports success and any errors or warnings in a structured form, so a build script can fail loudly when something goes wrong.

if (!result.success) {
  for (const error of result.errors) console.error(error.text);
  Deno.exit(1);
}

The bundle is a single ordinary JavaScript file with the @std/text code inlined. It runs anywhere, with no imports left to resolve.

const stat = await Deno.stat("dist/app.js");
console.log(`bundled ${stat.size} bytes`); // bundled 462 bytes

Run it to prove it is self-contained. Deno.spawnAndWait is a shorthand for Deno.Command; pass stdout: "piped" to capture the output instead of inheriting the terminal.

const output = await Deno.spawnAndWait(Deno.execPath(), {
  args: ["run", "dist/app.js"],
  stdout: "piped",
});
console.log(new TextDecoder().decode(output.stdout)); // helloFromTheBundle

Run this example locally using the Deno CLI:

deno run --unstable-bundle --allow-read --allow-write --allow-env --allow-net https://docs.deno.com/examples/scripts/deno_bundle.ts

Bundle code with Deno.bundle

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