deno transpile

The deno transpile command emits JavaScript from TypeScript, JSX, or TSX sources. It's useful when you need plain .js output to ship to a runtime that doesn't understand TypeScript, or to feed into a build step that expects JavaScript.

For most workflows you do not need deno transpile — deno run, deno test, and deno serve already accept .ts / .tsx files directly. Reach for it when:

• You're shipping a library to consumers that run node or a browser bundler directly. (For npm tarballs, prefer deno pack, which wraps deno transpile with packaging logic.)
• A downstream tool only understands .js.
• You want pre-compiled .js checked into a build artifact rather than transpiled on the fly.

Usage Jump to heading#

deno transpile <files...> [flags]

<files> is one or more source file paths (globs are expanded by the shell). deno transpile does not crawl a directory — pass the files you want transpiled, optionally via a shell glob.

Output modes Jump to heading#

# Print to stdout
deno transpile main.ts

# Write to a single file
deno transpile main.ts -o dist/main.js

# Transpile multiple files into an output directory
deno transpile src/main.ts src/helpers.ts --outdir dist

# Use a shell glob
deno transpile src/*.ts --outdir dist

Input / output extension mapping Jump to heading#

JSX transform, decorators, target, and other emit settings come from compilerOptions in your deno.json (or tsconfig.json), so the output matches what deno run would execute. See TypeScript compiler options for the full list.

Source maps Jump to heading#

Pass --source-map with one of:

deno transpile main.ts -o dist/main.js --source-map separate

Type declarations Jump to heading#

Use --declaration to emit .d.ts declaration files. Declarations are produced by tsc (using the bundled TypeScript), so this flag honors the compilerOptions from your deno.json / tsconfig.json.

.d.ts files are always written to disk — next to the source when no output location is set, or into --outdir when one is supplied — even if the JavaScript output is going to stdout or a single -o file.

deno transpile src/*.ts --outdir dist --declaration

How it differs from tsc Jump to heading#

deno transpile and TypeScript's tsc overlap, but they aren't drop-in replacements for each other:

If you want type errors to surface, run deno check before or after transpilation. deno transpile will happily emit code that fails to type-check.

Caveats Jump to heading#

• No bundling. Each input file produces one output file. Imports are rewritten extension-only (./foo.ts → ./foo.js) but the resulting graph still requires a runtime that resolves the imports. For a single-file output, use deno bundle.
• No directory crawl. Passing a directory does nothing — pass the files explicitly (src/**/*.ts) or via a glob.
• Source maps and stdout. --source-map inline works when writing to stdout; separate requires an output path it can write the map next to.

See also Jump to heading#

• deno bundle — produce a single bundled JavaScript file
• deno pack — build an npm-publishable tarball (uses deno transpile internally)
• deno check — type-check without emitting
• TypeScript support — overview of how TypeScript works in Deno

deno transpile [OPTIONS] [file]...

deno transpile main.ts

deno transpile main.ts -o main.js

deno transpile src/*.ts --outdir dist

deno transpile main.ts --source-map separate

deno transpile main.ts -o out.js --declaration