PascalCase vs. camelCase: Naming Conventions for Clean Code

Coding may seem as simple as typing on a keyboard to create custom scripts or applications, but consistency throughout the codebase is essential in ensuring what you’re making is usable. One way to ensure consistency in collaborative development projects is through casing, or the style in which programmers combine and separate words within variables, functions, classes or any other identifiers in a program. There are four commonly used casings in modern programing:

1. camelCase
2. PascalCase
3. snake_case
4. kebab-case 

Each casing style has its own set of rules and conventions, and understanding the differences between them is essential for writing clean and readable code. Understanding the differences between each casing style is critical to writing better code. Let’s dive into each case and explore their characteristics and preferred usage in different programming languages.

Why Are Casing Styles Needed in Programming?

In programming, identifiers such as variables and functions cannot contain spaces or reserved characters. To maintain readability when combining two or more words to name an identifier, programmers use casing styles to ensure clarity and consistency throughout their code. 

By using a specific casing style across their codebase, developers can quickly distinguish different elements with a glance. When collaborating with other developers, casings also maintain a uniform style, ensuring others can read and understand the codebase.

What Is camelCase?

camelCase is a casing style where words are joined together without any spaces, and each new word starts with a capital letter except for the first word. The name "camelCase" comes from the hump-like appearance of the capital letters. camelCase is commonly used in JavaScript, Java and C# for variable and function names.

camelCase Example

let firstName = "John";
let lastName = "Doe";

function printFullName(firstName, lastName) {
    let fullName = firstName + " " + lastName;
    console.log(fullName);
}

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What Is PascalCase?

PascalCase is similar to camelCase, but unlike camelCase, the first letter of each word is capitalized, such as: "PascalCase". PascalCase is commonly used in naming classes, interfaces and other types in languages like C#, Java and TypeScript.

PascalCase Example

class Person {
    firstName: string;
    lastName: string;

    constructor(firstName: string, lastName: string) {
        this.firstName = firstName;
        this.lastName = lastName;
    }

    printFullName(): void {
        let fullName = this.firstName + " " + this.lastName;
        console.log(fullName);
    }
}

What Is snake_case?

snake_case is a casing style where words are separated by underscores (_). It’s called "snake_case" because the underscores resemble the belly scales of a snake. snake_case is typically used in languages like Python, Ruby and JavaScript for variable and function names.

snake_case Example

first_name = "John"
last_name = "Doe"

def print_full_name(first_name, last_name):
    full_name = first_name + " " + last_name
    print(full_name)

What kebab-case?

kebab-case is a casing style where words are separated by hyphens (-), as in: "kebab-case". kebab-case is commonly used in URLs, file names and HTML/CSS class names.

kebab-case Example

<div class="user-profile">
    <p>This is a user profile.</p>
</div>

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When to Use PascalCase vs. camelCase and Others

This is a general rule of thumb for when to use what casing:

1. camelCase: Go, JavaScript, Java and C# for variable and function names.
2. PascalCase: Go, C#, Java and TypeScript for class and type names.
3. snake_case: Python, Ruby and JavaScript  for variable and function names.
4. kebab-case: HTML and CSS for class names, file names and URLs.

It’s important to note, however, that these are general conventions, and different programming communities and organizations may have their own preferred casings. The key is to be consistent within your codebase and follow the style guide of the programming language or framework you are using. Consistent and clear naming conventions contribute to the readability and maintainability of code, making it easier for yourself and others to understand and work with.

The choice of casing style depends on the programming language and the specific context of its usage. snake_case, camelCase, PascalCase and kebab-case each have their own rules and purposes. By understanding their differences and adhering to the conventions of your chosen language, you can write code that is more readable and maintainable.

Frequently Asked Questions

class Person {
    firstName: string;
    lastName: string;

    constructor(firstName: string, lastName: string) {
        this.firstName = firstName;
        this.lastName = lastName;
    }

    printFullName(): void {
        let fullName = this.firstName + " " + this.lastName;
        console.log(fullName);
    }
}

let firstName = "John";
let lastName = "Doe";

function printFullName(firstName, lastName) {
    let fullName = firstName + " " + lastName;
    console.log(fullName);
}