Names are case-sensitive, lowercase and uppercase are different.
Start variable names with a letter, use camelCase for names.
Variable names should be self-descriptive, describing the stored value.
Boolean variables are usually prefixed with is or has.
Functions
Names are case-sensitive, lowercase and uppercase are different.
Start function names with a letter, use camelCase for names.
Use descriptive names, usually verbs in the imperative form.
Common prefixes are get, make, apply etc.
Class methods follow the same rules.
Constant
Names are case-sensitive, lowercase and uppercase are different.
Define constants at the top of your file, function or class.
Sometimes UPPER_SNAKE_CASE is used, while other times plain camelCase.
Classes
Names are case-sensitive, lowercase and uppercase are different.
Start class names with a capital letter, use PascalCase for names.
Use descriptive names, explaining the functionality of the class.
Components, which are used in frontend frameworks follow the same rules.
Private
Prefix any variable or function with _ to show intention for it to be private.
As a convention, this will not prevent other parts of the code from accessing it.
Written by Angelos Chalaris
I'm Angelos Chalaris, a JavaScript software engineer, based in Athens, Greece. The best snippets from my coding adventures are published here to help others learn to code.
If you want to keep in touch, follow me on GitHub or Twitter.
One of the most commonly asked JavaScript interview questions is about hoisting. It's also a concept that might require some getting used to, so read our guide to learn more.
JavaScript variables can be declared a handful of ways. However, they're not all created equal and understanding their differences can drastically change the way you code.
JavaScript developers often get confused by JavaScript's variables and scope. Here's a quick guide to understanding and remembering everything related to these concepts.