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# lodash.snakecase
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The lodash method `_.snakeCase` exported as a standalone Node.js module for converting strings to snake_case format. This utility transforms various string formats including camelCase, PascalCase, kebab-case, and space-separated words into consistent snake_case output with lowercase words separated by underscores.
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## Package Information
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- **Package Name**: lodash.snakecase
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- **Package Type**: npm
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- **Language**: JavaScript
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- **Installation**: `npm install lodash.snakecase`
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- **Version**: 3.1.1
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- **License**: MIT
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## Core Imports
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```javascript
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var snakeCase = require('lodash.snakecase');
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```
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For ES6 modules (with transpiler):
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```javascript
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import snakeCase from 'lodash.snakecase';
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```
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## Basic Usage
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```javascript
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var snakeCase = require('lodash.snakecase');
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// Convert camelCase
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console.log(snakeCase('fooBar'));
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// => 'foo_bar'
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// Convert PascalCase  
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console.log(snakeCase('FooBar'));
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// => 'foo_bar'
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// Convert kebab-case
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console.log(snakeCase('--foo-bar'));
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// => 'foo_bar'
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// Convert space-separated words
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console.log(snakeCase('Foo Bar'));
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// => 'foo_bar'
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// Handle empty input
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console.log(snakeCase(''));
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// => ''
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```
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## Capabilities
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### String Conversion
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Converts strings to snake_case format by extracting words and joining them with underscores.
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```javascript { .api }
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/**
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 * Converts string to snake case format
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 * @param {string} [string=''] The string to convert
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 * @returns {string} Returns the snake cased string
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 */
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function snakeCase(string)
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```
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**Parameters:**
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- `string` (string, optional): The string to convert. Defaults to empty string if not provided.
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**Returns:**
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- (string): The converted string in snake_case format with lowercase words separated by underscores.
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**Behavior:**
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- Removes accents and diacritical marks from characters
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- Extracts words from the input string (handles camelCase, PascalCase, kebab-case, spaces, punctuation)
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- Converts all words to lowercase
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- Joins words with underscore separators
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- Returns empty string for null, undefined, or empty input
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**Usage Examples:**
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```javascript
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var snakeCase = require('lodash.snakecase');
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// Various input formats
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snakeCase('Foo Bar');           // => 'foo_bar'
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snakeCase('fooBar');            // => 'foo_bar'  
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snakeCase('FooBar');            // => 'foo_bar'
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snakeCase('--FOO-BAR--');       // => 'foo_bar'
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snakeCase('foo2bar');           // => 'foo_2_bar'
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snakeCase('foo-bar_baz');       // => 'foo_bar_baz'
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// Special characters and accents
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snakeCase('résumé');            // => 'resume'
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snakeCase('café-société');      // => 'cafe_societe'
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// Numbers and mixed content
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snakeCase('version2Beta');      // => 'version_2_beta'
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snakeCase('XMLHttpRequest');    // => 'xml_http_request'
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// Edge cases
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snakeCase('');                  // => ''
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snakeCase(null);                // => ''
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snakeCase(undefined);           // => ''
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```
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## Implementation Details
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The function uses lodash helper utilities for processing:
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- `lodash.deburr`: Removes accents and diacritical marks from characters
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- `lodash.words`: Extracts words from strings using Unicode word boundaries
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The implementation follows a composable pattern where the input string is:
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1. Processed through `deburr` to normalize accented characters
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2. Split into words using the `words` function  
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3. Reduced to a single string with underscores between lowercase words