es-check-min

CLI tool and library to find the minimum compatible ECMAScript version of a JavaScript file.

Overview

A simple tool built on es-check to find the lowest supported ECMAScript version of a JavaScript file.

The es-check-min tool does not require any arguments, and simply runs a loop to determine the file's lowest compatible ECMAScript version. This is in slight contrast to es-check which checks a file against a specified ECMAScript version.

Detection of the following ECMAScript versions is supported:

• ES5
• ES6 / ES2015
• ES7 / ES2016
• ES8 / ES2017
• ES9 / ES2018
• ES10 / ES2019
• ES11 / ES2020
• ES12 / ES2021
• ES13 / ES2022

Note: The underlying es-check implementation technically supports ES3 and ES14 / ES2023, but certain tests aren't passing against these targets so they are not currently returned.

Getting started

Dependencies

• Node.js 24.16.0 or newer (specifically ^24.16.0 || >=26.3.0)

The exported library APIs are ESM-only.

Installation

Pick the option that matches how you plan to use it.

As a library

Add it to your project to import the TypeScript API. This also puts the es-check-min CLI on your project's path:

npm install es-check-min

As a CLI tool

Run it once without installing:

npx es-check-min <file>

Or install it globally with Homebrew:

brew install kitschpatrol/tap/es-check-min

Or install it globally with npm:

npm install --global es-check-min

Usage

CLI

Example

es-check-min ./mystery-file.js

prints...

es6/es2015

Commands

Command: es-check-min

Get the minimum supported ECMAScript version of a JavaScript file.

Usage:

es-check-min <file>

| Positional Argument | Description | Type | | ------------------- | ------------------------------------- | -------- | | file | Path to the JavaScript file to check. | string |

| Option | Description | Type | | ------------------- | ------------------- | --------- | | --help-h | Show help | boolean | | --version-v | Show version number | boolean |

Library

A single function is exported:

function esCheckMin(path: string): Promise<EsVersion | undefined>

Background

Requests for something like this have come up once or twice:

• Make babel tell me the minimum version of target that supports my code
• Feature Request: Wrapper command for "minimum ES version" for a file

Maintainers

kitschpatrol

Acknowledgments

es-check-min is just a trivial wrapper over es-check. All credit goes to Jeff Wainwright and contributors for creating and maintaining es-check.

Contributing

Issues are welcome and appreciated.

Please open an issue to discuss changes before submitting a pull request. Unsolicited PRs (especially AI-generated ones) are unlikely to be merged.

This repository uses @kitschpatrol/shared-config (via its ksc CLI) for linting and formatting, plus MDAT for readme placeholder expansion.

License

MIT © Eric Mika