In JavaScript, variables are named following specific conventions to make the code more readable and maintainable. Here are the key rules and practices:
Case Sensitivity: Variable names are case-sensitive, meaning
myVariable
andmyvariable
are different variables.Letters, Numbers, Symbols: Variable names can include letters, numbers, and certain symbols like
$
and_
. However, they cannot start with a number.No Reserved Keywords: You can't use JavaScript reserved words (like
var
,function
,return
) as variable names.Descriptive Names: Variable names should be descriptive and meaningful, reflecting the data they store. This makes the code easier to understand.
Camel Case: The most common convention is camelCase, where the first word is lowercase, and the first letter of subsequent words is capitalized (e.g.,
myVariableName
).Snake Case: Less common but sometimes used, especially in constants, is snake_case, where words are separated by underscores (e.g.,
my_variable_name
).Pascal Case: Often used for class names, PascalCase capitalizes the first letter of every word (e.g.,
MyVariableName
).Short but Descriptive: Names should be concise but still give a clear idea of the variable's purpose. Avoid overly long or overly short names.
Avoid Special Characters: Stick to letters, numbers,
$
, and_
. Avoid other symbols to prevent errors and confusion.Consistency: Stick to a consistent naming pattern throughout your code to make it easier to read and maintain.
10 Examples of JavaScript Variable Naming Conventions
userName
- Camel CasetotalAmount
- Camel CaseisActive
- Camel Case for booleansMAX_SIZE
- All uppercase with underscores (for constants)user_age
- Snake CaseMyClassName
- Pascal Case (for class names)$element
- Common for variables storing DOM elements_tempValue
- Starting with an underscore (often used for private variables)itemCount2
- Using a number at the end (but not the beginning)dataList
- Simple Camel Case for an array or list