Let’s look at the most common compound word naming styles.
When writing code, it is often necessary to name something (a class, variable, method, parameter, etc.), and it is critically important that the name is clear and understandable to others. However, a typical language parser treats each word as a separate token. This is why compound words are often used in naming. It is essential to choose a consistent naming style to maintain uniformity across a project or workspace.
Compound word styles
| Naming style | Example |
|---|---|
| Raw string with spaces | some awesome var |
| Camel Case | someAwesomeVar |
| Snake Case | some_awesome_var |
| Kebab Case | some-awesome-var |
| Pascal Case | SomeAwesomeVar |
| Upper Case Snake Case | SOME_AWESOME_VAR |
camelCase
In camelCase, the name starts with a lowercase letter, and each subsequent word starts with an uppercase letter. All words are written together without spaces or separators.
Example of camelCase for the phrase camel case var – camelCaseVar.
snake_case
To use the snake_case style, replace spaces with underscores. All letters are lowercase. Sometimes snake_case is mixed with camelCase or PascalCase, but this decreases readability and defeats the purpose of having a consistent style.
Example of snake_case for the phrase snake case var – snake_case_var.
kebab-case
kebab-case is similar to snake_case, but uses hyphens instead of underscores. All letters are lowercase. This style can also be mixed with others, but doing so has little benefit and typically adds confusion.
Example of kebab-case for the phrase kebab case var – kebab-case-var.
One additional thing to consider when using kebab-case is how most text editors treat it: each segment separated by a hyphen is recognized as an individual word. As a result, double-clicking highlights only one segment (e.g., kebab or case), and when navigating with the keyboard, the cursor moves between segments instead of jumping across the entire compound word. This can make editing less convenient compared to styles like camelCase or snake_case, where the name is treated as a single word.
PascalCase
In PascalCase, every word starts with an uppercase letter (unlike camelCase, where the first word starts lowercase).
Example of PascalCase for the phrase pascal case var – PascalCaseVar.
Note: This style is often confused with camelCase, but it is a distinct naming convention.
UPPER_CASE_SNAKE_CASE
In UPPER_CASE_SNAKE_CASE, all letters are uppercase and words are separated by underscores.
Example of UPPER_CASE_SNAKE_CASE for the phrase upper case snake case var – UPPER_CASE_SNAKE_CASE_VAR.
Usage recommendations
File names
For manually created files, it is advisable to use the snake_case notation. This preserves readability and reduces the risk of issues on case-sensitive file systems. For example, a file might be named using PascalCase, but a developer might refer to it in code using camelCase. On Windows or macOS, this discrepancy typically goes unnoticed, but on Linux, where the file system is case-sensitive, it can lead to runtime errors. Using snake_case for file names helps avoid such problems.