esmon

library2.0.1jsnpmunverified

A fast file-watching runner and build tool for scripts, powered by esbuild. Version 2.0.1 uses esbuild for rapid compilation and restarting, with automatic dependency tracking, external module exclusion, and optional ESM output. It supports TypeScript decorators via swc and runs multiple commands (watch, run, build). Maintained by egoist, with regular updates. Differentiators: leverages esbuild's speed, built-in build command, and automatic watch of imported files.

devops http-networking

npm install esmon

package ↗

INSTALL

IMPORT

SIG · ESMON

esmon

devopsjavascriptv2.0.1

harness data pending

Install & Compatibility

Where this runs

No compatibility data collected yet for this library.

Code

Verified usage

Verified import paths — ran on the pinned version, not inferred.

esmon (CLI)

✓ npx esmon your-script.ts

✗ npm start esmon your-script.ts

esmon is primarily a CLI tool, not a library.

run

✓ esmon run your-script.ts

✗ esmon your-script.ts (without run flag runs watch mode)

The default command is watch; use 'run' to execute without watching.

build

✓ esmon build your-script.ts

✗ esmon build your-script.ts --format esm (flag is --esm)

Use --esm for ESM output, not --format esm.

Install esmon as a dev dependency and run a TypeScript script with file watching.

npm i -D esmon esmon your-script.ts

esmon --version

Debug

Known issues

gotchaTemporary files are emitted to ./temp folder; add to .gitignore.

fix

Add 'temp/' to your .gitignore file.

affects: >=2.0.0

gotchaDefault command watches files; use 'run' to execute once.

fix

Run 'esmon run your-script.ts' instead of 'esmon your-script.ts'.

affects: >=2.0.0

gotchaESM output uses --esm flag, not --format esm.

fix

Use 'esmon build --esm your-script.ts'.

affects: >=2.0.0

gotchaDecorators require emitDecoratorMetadata in tsconfig.json; uses swc.

fix

Enable emitDecoratorMetadata in tsconfig.json.

affects: >=2.0.0

gotchadevDependencies excluded by default; use --bundleDevDeps to include.

fix

Pass --bundleDevDeps flag to include devDependencies in bundle.

affects: >=2.0.0

Errors

Common errors & fixes

Error: Cannot find module 'esbuild'

esbuild is not installed or not in node_modules.

fix

Run 'npm install esbuild' or add it as a dependency.

Command not found: esmon

esmon is not installed globally or locally.

fix

Run 'npm install -D esmon' in your project directory.

TypeError: __dirname is not defined

Using CommonJS __dirname in ESM output.

fix

Use --esm flag or import.meta.url for ESM.

Error: Decorator metadata not supported

emitDecoratorMetadata not enabled in tsconfig.json.

fix

Set 'emitDecoratorMetadata': true in tsconfig.json compilerOptions.

Build failed: Unexpected token

Incompatible JavaScript/TypeScript syntax with esbuild.

fix

Ensure your code uses supported syntax; update esbuild version.

Upgrade

Version history

2.0.1latest on npm

Audit

Dependencies

No dependency data recorded yet.

Agent activity

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Resources

packagehttps://www.npmjs.com/package/esmon ↗