All JavaScript Variables Need to Obey These Fundamental Rules

Basic principles for valid JavaScript variable names

Photo by Claudio Schwarz on Unsplash

Variables are the workhorses of JavaScript, holding the data that make your software tick — and they are everywhere.

Here are some fundamental rules that all valid JavaScript variable names should obey to avoid errors and for maintainable code.

• A variable name should be one word, with no spaces.
• Use alphabetical characters (a-z), numbers (0–9), and the underscore character (_). This is to avoid errors and for syntax compatibility.
• Variables names can’t begin with a number otherwise you’ll get an error. This is because JavaScript uses numbers as a separate data type. For example, 1name is invalid, but firstName is okay.
• Variable names are case-sensitive. For example, the variable names: myage, MyAge, myAge and MYAGE are four distinct variables. The key here is to be consistent in your naming/capitalization to avoid unintended behavior.
• Don’t use reserved JavaScript keywords (such as else, function, if etc.) Because they have a special meaning within JavaScript.

Again, be consistent in your naming. The most widely adopted convention for variable names is camelCase. For example, firstName, lastName, and isLoggedIn etc.