Skip to main content

Variable naming rules and comments

JavaScript has a naming convention that it uses in naming JavaScript variables.

The naming convention is made up of a set of rules and the rules are:

  • Javascript is case sensitive hence the variables should be case sensitive.
  • JavaScript does not allow spaces in variables. The names must be written together.
  • Variable names begin with a letter or dollar sign($) or an underscore.
  • Names can contain letters, numbers, dollar signs and underscores.
  • You cannot use reserved words (words with special use and special meaning) as a variable name.

Failure to obey these rules will lead to an error when you are writing a program.

Note: It is best practice to use camelCase when naming variables. The first name begins with a small letter and the other name that follows is a capital letter.

Using camelCase pattern when naming variables will not give an error when you are writing program but it is considered best practice.

Common best practices when naming variables in Javascript​

There are other best practices you should know when naming variables and they are:

  • Use meaningful words as variables. It is best to give your variables a name that relate with the program. Eg, in a calculator program, you could use a variable with the name, inputButton.
  • You can use multiple names to name a variable as long as it describes the variables well.
  • When using multiple words, you could use the camelCase pattern or underscores (_) to join the words.

Comments​

To use comments in JavaScript, you use two different patterns for single line comments and multiple line comments.

Example,

main.js

const data = 2;         //this is a one line comment


/*
This is a multi-line comment. It is used when a comment exceeds a single line.
*/