json2yaml: JSON to YAML Converter

Common errors

• ReferenceError: require is not defined

  cause Attempting to use `require()` in an ES Module environment or a browser without a CommonJS bundler.
  fix Ensure your Node.js project is running in a CommonJS context (e.g., `"type": "commonjs"` in `package.json` or explicitly using `.cjs` file extensions). For browsers, use a bundler like Webpack or Rollup that handles CommonJS modules.

• TypeError: json2yaml.stringify is not a function

  cause Incorrectly importing or accessing the `stringify` method, or attempting to call the default export directly as a function.
  fix Ensure you are using `const json2yaml = require('json2yaml');` and then calling `json2yaml.stringify(data);`. The `stringify` method is a property of the module's default export.

• json2yaml: command not found

  cause The `json2yaml` command-line utility is not in your system's PATH, usually because it was not installed globally or npm's global bin directory is not in PATH.
  fix Install the package globally using `npm install -g json2yaml`. If the problem persists, ensure your npm global bin directory is included in your system's PATH environment variable (e.g., `~/.npm-global/bin`).

Warnings

• breaking The package specifies Node.js >= 0.2.0 and has not been updated in over 9 years. It is highly likely to have compatibility issues with modern Node.js versions (v14+), especially regarding ES Modules, deprecated APIs, and event loop behavior.
  Fix: Consider using actively maintained alternatives like `js-yaml` or `yaml` for modern Node.js environments. If you must use `json2yaml`, run it in a legacy Node.js environment or a container configured with older Node.js versions.
• gotcha This package is CommonJS-only. Attempting to use ES Modules `import` statements will result in `ReferenceError: require is not defined` or similar errors in pure ESM environments. You must use `require()` or configure your project for CJS interop.
  Fix: Ensure your project is configured for CommonJS (e.g., `"type": "commonjs"` in `package.json`) or use dynamic `import()` if you are in an ESM context and need to load a CJS module.
• gotcha As an unmaintained package, `json2yaml` is unlikely to receive security patches for newly discovered vulnerabilities. Using it in production environments is not recommended without thorough security audits.
  Fix: Prioritize using actively maintained libraries for security-sensitive applications. If this package is critical, consider auditing its source code or forking it for maintenance.
• gotcha The package does not ship with TypeScript declaration files (`.d.ts`). Usage in TypeScript projects will require manual type declarations or suppressing type checks for imports.
  Fix: Create a declaration file (e.g., `json2yaml.d.ts`) with `declare module 'json2yaml' { ... }` or use `@ts-ignore` on the import statement.

Install

• npm install json2yaml npm
• yarn add json2yaml yarn
• pnpm add json2yaml pnpm

Imports

• YAML
  wrong:

  import YAML from 'json2yaml';

  correct:

  const YAML = require('json2yaml');

  This package is CommonJS-only and exposes its API via `module.exports`. It does not support ES Modules `import` syntax, which will lead to runtime errors in environments not configured for CJS interop.
• stringify
  wrong:

  import { stringify } from 'json2yaml';

  correct:

  const { stringify } = require('json2yaml');
  // or
  const YAML = require('json2yaml');
  const ymlText = YAML.stringify(data);

  The primary function for programmatic conversion is exposed as 'stringify' on the default export. Direct named import using ES Module syntax is not supported.
• json2yaml (CLI)

  json2yaml <file.json> > <file.yml>

  The package is primarily designed for global command-line interface (CLI) use after `npm install -g json2yaml`.

Quickstart

This code snippet demonstrates how to use `json2yaml` programmatically to convert a JavaScript object (which translates to JSON) into a human-readable YAML string using the `stringify` method.

const json2yaml = require('json2yaml');

// Sample JSON data for conversion
const data = {
  product: 'Widget X',
  version: '1.0.0',
  features: [
    { name: 'Feature A', enabled: true },
    { name: 'Feature B', enabled: false, note: 'Experimental' }
  ],
  settings: {
    debugMode: false,
    logLevel: 'info'
  },
  nullValue: null,
  price: 99.99,
  available: true
};

try {
  // Convert the JSON object to a YAML string
  const yamlOutput = json2yaml.stringify(data);
  console.log('--- Converted YAML Output ---\n');
  console.log(yamlOutput);
} catch (error) {
  console.error('An error occurred during JSON to YAML conversion:', error.message);
}