Convert Text to camelCase

Converting Text to camelCase

camelCase joins multiple words together, removing all spaces and delimiters, capitalizing the first letter of each word except the first. It gets its name from the "humps" created by the capital letters in the middle of the identifier.

Basic Conversion

Input:  user first name
Output: userFirstName

Input:  get-api-response
Output: getApiResponse

Input:  MAX_RETRY_COUNT
Output: maxRetryCount

How Word Boundaries Are Detected

A good camelCase converter recognizes multiple types of word boundaries:

1. Spaces: "hello world" → helloWorld
2. Hyphens: "background-color" → backgroundColor
3. Underscores: "created_at" → createdAt
4. Case transitions: "XMLParser" → xmlParser (uppercase runs followed by lowercase)
5. Dots: "my.variable.name" → myVariableName

Where camelCase Is Used

camelCase is the dominant naming convention in several ecosystems:

// JavaScript / TypeScript — variables, functions, methods
const userName = "Alice";
function getUserProfile(userId) { /* ... */ }
element.addEventListener("click", handleClick);

// Java — variables, methods, parameters
String firstName = "Alice";
public void setUserName(String name) { /* ... */ }

// JSON keys (by convention)
{ "firstName": "Alice", "lastName": "Smith" }

camelCase vs. PascalCase

The difference is simple: camelCase starts with a lowercase letter, PascalCase starts with an uppercase letter. In JavaScript/TypeScript, the convention is:

• camelCase for variables, functions, methods, and properties
• PascalCase for classes, components, and types

Handling Acronyms

Acronyms in camelCase are debatable. Two common approaches:

"XML HTTP request" → xmlHttpRequest  (preferred — treat acronym as a word)
"XML HTTP request" → xmlHTTPRequest  (less common — preserve acronym)

Most style guides (Google, Airbnb) recommend lowering acronyms to improve readability.

Edge Cases

• Single word: "hello" → "hello" (no change needed).
• Already camelCase: the input should pass through unchanged.
• Numbers: "item 2 count" → "item2Count".
• Leading/trailing delimiters: "--my-var--" → "myVar".