# Javascript

> Use for Babel presets, Webpack configs, and multi-target builds in contentstack-marketplace-sdk.

- Skill: `contentstack/javascript` (Agent Skill)
- Install (CLI): `npx skillmds@latest add contentstack/javascript`
- Raw SKILL.md: https://api.skillmd.com/api/skills/contentstack/javascript/raw
- Safety review: pending
- Works with: Claude Code, Claude.ai, OpenAI Codex
- Category: Coding & Dev Tools
- Author: contentstack (https://skillmd.com/u/contentstack)
- Updated: 2026-09-17
- Page: https://skillmd.com/skills/contentstack/javascript

---


# JavaScript tooling – contentstack-marketplace-sdk

## When to use

- Editing **`webpack/*.js`** or Babel envs (`es5`, `es-modules`, `test`)
- Debugging environment-specific bundles (Node vs browser vs RN)

## Instructions

### Babel

- Builds use **`BABEL_ENV`** (`es5`, `es-modules`, `test`)—ensure new syntax is transpiled for the oldest supported runtime of each target.

### Webpack

- Separate configs per platform (`webpack.node.js`, `webpack.web.js`, etc.)—keep shared settings DRY via `webpack-merge` where the repo already does.

### Types

- TypeScript definitions live under **`types/`**—update when public JS surface changes.