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snakeCase ​

The snake_case utility transforms a string into snake_case format (all lower case with words separated by underscores). It is commonly used for database column names, file naming conventions, or environment variables.

Source Code ​

View Source Code
ts
import { normalizeCase } from './_caseUtils';

/**
 * Converts a string to snake case.
 *
 * @example
 * ```ts
 * const text = 'Hello World';
 * toSnakeCase(text) // 'hello_world';
 * ```
 *
 * @param str - The string to convert.
 *
 * @returns The converted string.
 */
export function snakeCase(str: string): string {
  return normalizeCase(str, '_').toLowerCase();
}

Features ​

  • Isomorphic: Works in both Browser and Node.js.
  • Durable Parsing: Handles spaces, dashes, and dots as separators.
  • Case Boundary Detection: Correctly splits strings based on transitions between lower and upper case (e.g., from camelCase).

API ​

ts
function snakeCase(input: string): string;

Parameters ​

  • input: The string to transform.

Returns ​

  • The transformed string in snake_case.

Examples ​

Basic Conversion ​

ts
import { snakeCase } from '@vielzeug/toolkit';

snakeCase('hello world'); // 'hello_world'
snakeCase('fooBar'); // 'foo_bar'
snakeCase('Kebab-Case'); // 'kebab_case'
snakeCase('data.meta.id'); // 'data_meta_id'

Advanced Scenarios ​

ts
import { snakeCase } from '@vielzeug/toolkit';

snakeCase('  leading trailing  '); // 'leading_trailing'
snakeCase('XMLHttpRequest'); // 'xml_http_request'
snakeCase('multiple---dashes'); // 'multiple_dashes'

Implementation Notes ​

  • Trims input and removes leading/trailing separators.
  • Collapses consecutive separators into a single underscore.
  • Throws TypeError if the input is not a string.

See Also ​