Camel case is named for the visual resemblance of its capitalized letters within a word or phrase to the humps on a camel's back.
Understanding Camel Case
Camel case is a style of writing compound words or phrases without spaces, where the first letter of each word (after the first word) is capitalized. The very first letter of the entire compound word can be either lowercase or uppercase, leading to different variations of camel case. This convention is widely used to create readable identifiers or names in contexts where spaces are not permitted, such as in programming.
Here are some common examples illustrating this style:
myVariable(first letter lowercase)calculateTotalAmount(first letter lowercase)ClassName(first letter uppercase)UserService(first letter uppercase)
The Origin of the Name
The distinctive name "camel case" directly stems from its unique visual appearance. When a phrase or compound word is written using this convention, the uppercase letters that appear in the middle of the word stand out above the surrounding lowercase letters. This creates a rising and falling pattern, much like the peaks and valleys, or "humps," found on a camel's back. This intuitive analogy makes the name both descriptive and memorable.
Types and Practical Usage
While often referred to simply as "camel case," there are two primary forms, distinguished by the capitalization of the initial letter:
| Type | Description | Example | Common Use Case |
|---|---|---|---|
| Lower Camel Case | The first letter of the entire compound word is lowercase, with subsequent words starting uppercase. | userName |
Variables, function names, method names in languages like JavaScript, Java, Swift. |
| Upper Camel Case | The first letter of the entire compound word is uppercase, with subsequent words also starting uppercase. | DatabaseManager |
Class names, interface names, type definitions (also known as Pascal Case). |
Camel case is a highly popular naming convention across various domains, especially in software development, due to its ability to enhance readability while adhering to syntax rules:
- Programming Languages: It is a fundamental naming convention for variables, functions, methods, classes, and types in many widely used programming languages (e.g., JavaScript, Java, C#, Objective-C, Swift).
- Web Development: Frequently used for naming CSS properties (like
backgroundColororfontSize), JavaScript object keys, and HTML DOM properties. - APIs and Data Structures: Common for naming parameters, fields, and properties in JSON, XML, or other data structures exchanged via APIs.
- File Naming: Less common but occasionally used for file or folder names where spaces are cumbersome or prohibited by the operating system.
This convention helps developers and readers quickly discern the boundaries between words in a compound identifier, contributing to cleaner and more maintainable code and text.
