Text Case Converter — Developer Code Samples

Convert text between different naming conventions: camelCase for JavaScript, snake_case for Python, PascalCase for classes, and kebab-case for CSS. These utilities are essential for code generators, API bridges, and linting tools.

Try the interactive version online: Open Text Case Converter Tool →

Parameters

Parameter	Type	Required	Description
text	str	Yes	Input text in any case format
to_case	str	Yes	Target case: snake, camel, pascal, kebab, constant, title (required)

Returns: String converted to the specified naming convention

Code Examples

import re

def to_snake_case(text):
    """Convert any case to snake_case."""
    # Handle camelCase and PascalCase
    text = re.sub(r'([A-Z]+)([A-Z][a-z])', r'\1_\2', text)
    text = re.sub(r'([a-z\d])([A-Z])', r'\1_\2', text)
    # Replace spaces and hyphens
    text = re.sub(r'[\s-]+', '_', text)
    return text.lower()

def to_camel_case(text):
    """Convert any case to camelCase."""
    text = to_snake_case(text)
    parts = text.split('_')
    return parts[0] + ''.join(p.capitalize() for p in parts[1:])

def to_pascal_case(text):
    """Convert any case to PascalCase."""
    text = to_snake_case(text)
    return ''.join(p.capitalize() for p in text.split('_'))

def to_kebab_case(text):
    """Convert any case to kebab-case."""
    return to_snake_case(text).replace('_', '-')

def to_title_case(text):
    """Convert to Title Case (capitalize each word)."""
    return re.sub(r"[A-Za-z]+('[A-Za-z]+)?", lambda m: m.group(0).capitalize(), text)

def to_constant_case(text):
    """Convert to CONSTANT_CASE (uppercase snake)."""
    return to_snake_case(text).upper()

# Examples
inputs = ["hello world", "helloWorld", "HelloWorld", "hello-world", "HELLO_WORLD"]
for inp in inputs:
    print(f"Input: {inp!r}")
    print(f"  snake_case:    {to_snake_case(inp)}")
    print(f"  camelCase:     {to_camel_case(inp)}")
    print(f"  PascalCase:    {to_pascal_case(inp)}")
    print(f"  kebab-case:    {to_kebab_case(inp)}")
    print(f"  CONSTANT_CASE: {to_constant_case(inp)}")

// Convert any case to snake_case
function toSnakeCase(str) {
  return str
    .replace(/([A-Z]+)([A-Z][a-z])/g, '$1_$2')
    .replace(/([a-z\d])([A-Z])/g, '$1_$2')
    .replace(/[\s-]+/g, '_')
    .toLowerCase();
}

// Convert to camelCase
function toCamelCase(str) {
  return toSnakeCase(str)
    .replace(/_([a-z])/g, (_, c) => c.toUpperCase());
}

// Convert to PascalCase
function toPascalCase(str) {
  const camel = toCamelCase(str);
  return camel.charAt(0).toUpperCase() + camel.slice(1);
}

// Convert to kebab-case
function toKebabCase(str) {
  return toSnakeCase(str).replace(/_/g, '-');
}

// Convert to CONSTANT_CASE
function toConstantCase(str) {
  return toSnakeCase(str).toUpperCase();
}

// Convert to Title Case
function toTitleCase(str) {
  return str.replace(/\b\w/g, c => c.toUpperCase());
}

// Test all conversions
const inputs = ["hello world", "helloWorld", "HelloWorld", "hello-world"];
inputs.forEach(inp => {
  console.log(`Input: "${inp}"`);
  console.log(`  snake_case:    ${toSnakeCase(inp)}`);
  console.log(`  camelCase:     ${toCamelCase(inp)}`);
  console.log(`  PascalCase:    ${toPascalCase(inp)}`);
  console.log(`  kebab-case:    ${toKebabCase(inp)}`);
  console.log(`  CONSTANT_CASE: ${toConstantCase(inp)}`);
});

# Convert to lowercase
echo "Hello World" | tr '[:upper:]' '[:lower:]'

# Convert to uppercase
echo "hello world" | tr '[:lower:]' '[:upper:]'

# Spaces to underscores (snake_case)
echo "hello world foo" | tr ' ' '_'

# Spaces to hyphens (kebab-case)
echo "hello world foo" | tr ' ' '-'

# Title case with awk
echo "hello world foo" | awk '{for(i=1;i<=NF;i++) $i=toupper(substr($i,1,1)) substr($i,2); print}'

# camelCase to snake_case with sed
echo "helloWorldFoo" | sed 's/\([A-Z]\)/_\L\1/g; s/^_//'

# Python one-liner for any conversion
python3 -c "
import re, sys
text = sys.argv[1]
snake = re.sub(r'([a-z])([A-Z])', r'\1_\2', text).lower()
print(snake)
" "helloWorldFooBar"

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