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# Methods
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Methods is a utility library that provides an array of lowercase HTTP method names supported by Node.js. It serves as a cross-platform compatibility layer by using Node.js core's `http.METHODS` when available, or falling back to a predefined list for older Node.js versions and browser environments.
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## Package Information
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- **Package Name**: methods
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- **Package Type**: npm
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- **Language**: JavaScript
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- **Installation**: `npm install methods`
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## Core Imports
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```javascript
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var methods = require('methods');
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```
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ES Modules (via transpilation/bundling):
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```javascript
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import methods from 'methods';
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```
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## Basic Usage
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```javascript
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var methods = require('methods');
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// methods is an array of lowercase HTTP method names
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console.log(methods);
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// ['get', 'post', 'put', 'head', 'delete', 'options', 'trace', ...]
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// Check if a method is supported
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var isSupported = methods.indexOf('get') !== -1;
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// Use in HTTP routing
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function isValidMethod(method) {
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  return methods.indexOf(method.toLowerCase()) !== -1;
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}
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// Use for validation in web frameworks
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if (methods.indexOf(req.method.toLowerCase()) === -1) {
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  throw new Error('Unsupported HTTP method');
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}
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```
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## Architecture
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Methods has a simple, minimalist architecture designed for maximum compatibility:
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- **Runtime Detection**: Uses feature detection to check for `http.METHODS` availability
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- **Fallback Strategy**: Provides a curated list of 27 HTTP methods for older Node.js versions and browsers
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- **Static Export**: Returns a pre-computed array that remains constant throughout application lifecycle
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- **Zero Dependencies**: Self-contained with no external dependencies, reducing bundle size and security surface
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The module exports a single array that is determined at load time based on the JavaScript environment.
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## Capabilities
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### HTTP Methods Array
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The main and only export of the methods package - an array of lowercase HTTP method names.
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```javascript { .api }
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/**
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 * Array of lowercase HTTP method names supported by Node.js
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 * @type {string[]}
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 */
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var methods = require('methods');
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```
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**Runtime Behavior:**
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- **Node.js 0.11+**: Returns `http.METHODS.map(method => method.toLowerCase())`
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- **Node.js 0.10 and below**: Returns predefined array of 27 HTTP methods  
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- **Browser environments**: Returns predefined array (http module not available)
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**Supported HTTP Methods:**
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The array contains all standard and extended HTTP methods in lowercase:
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- **Standard methods**: `get`, `post`, `put`, `head`, `delete`, `options`, `trace`, `patch`, `connect`
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- **WebDAV methods**: `copy`, `lock`, `mkcol`, `move`, `propfind`, `proppatch`, `unlock`, `mkactivity`, `checkout`, `merge`
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- **Other methods**: `purge`, `report`, `m-search`, `notify`, `subscribe`, `unsubscribe`, `search`
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**Properties:**
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- **Type**: Array of strings
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- **Mutability**: Should be treated as read-only
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- **Length**: Varies by Node.js version (27 methods in fallback, more in newer Node.js versions)
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- **Content**: All method names are lowercase
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- **Ordering**: Consistent within same Node.js version
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**Usage Examples:**
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```javascript
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var methods = require('methods');
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// Iterate through all methods
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methods.forEach(function(method) {
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  console.log('Supported method:', method);
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});
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// Check if specific method exists
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function hasMethod(methodName) {
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  return methods.indexOf(methodName.toLowerCase()) !== -1;
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}
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// Filter custom methods
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var standardMethods = methods.filter(function(method) {
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  return ['get', 'post', 'put', 'delete'].indexOf(method) !== -1;
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});
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// Use in express-like routing
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function createHandler(method, path, handler) {
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  if (!hasMethod(method)) {
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    throw new Error('Invalid HTTP method: ' + method);
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  }
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  // ... routing logic
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}
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```
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## Types
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```javascript { .api }
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/**
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 * The methods export type definition
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 * @typedef {string[]} Methods
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 * @description Array of lowercase HTTP method name strings
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 */
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```
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## Error Handling
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The methods package does not throw any exceptions during normal operation. It provides a static array that is determined at module load time and remains constant throughout the application lifecycle. The package will only fail if:
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- Node.js itself fails to load the `http` module (extremely rare)
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- The module file is corrupted or inaccessible
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No runtime validation or error checking is performed on the exported array.
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## Browser Compatibility
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The package works in browser environments via browserify or similar bundlers:
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```javascript
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// Works in browsers - http module is shimmed out
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var methods = require('methods');
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// Returns the predefined fallback list
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```
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## Version Information
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- **Current Version**: 1.1.2
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- **Node.js Support**: >= 0.6
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- **License**: MIT
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- **Repository**: jshttp/methods
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## Related Packages
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This package is commonly used as a dependency in:
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- HTTP frameworks (Express, Koa, etc.)
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- Routing libraries  
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- HTTP clients and servers
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- Method validation utilities
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- Web development tools