What characters are valid for JavaScript variable names?

javascript

unicode-identifiers

variable-names

future-proofing

byNikita Barsukov·Oct 26, 2024

In JavaScript, variables can begin with a letter (a-z or A-Z), dollar sign ($), or underscore (_). They can include digits (0-9), and Unicode characters in the subsequent characters:

let name;              // As classic as a cup of black coffee ☕
let $price;            // The price is right!
let _count;            // A universal tool of calculation 🧮
let Ωmega;             // Greek alphabet for the win!

Steer clear of reserved keywords and be mindful that variable names are case-sensitive.

Digging deeper: The nitty-gritty of variable names

Let's further dissect Unicode identifiers, potential library conflicts, and thoughtfully future-proofing your JavaScript variable names.

Talking in tongues: Unicode characters

With JavaScript, variable names aren't limited to English letters. It fully embraces diversity, supporting Unicode characters and thus opens the door to a wide world of written languages:

let 你好 = 'Hello';       // Or should we say Ni Hao? 🐼
let café = 3.50;         // Who doesn't love a good brew ☕?

However, refrain from using certain symbols or patterns that popular libraries reserve for their use. A sneak peek into the library documentation can save you from unforeseen errors.

Staying safe within ASCII bounds

For a universal appeal and to steer clear of potential compatibility issues with libraries that shun Unicode, adhere to the ASCII range (32-126). Especially crucial when your code needs to survive in varied environments.

The tool-belt to swear by

Does your variable name comply with the standards? Tools like the JavaScript variable name validator can validate your identifiers for compatibility with ECMAScript 5.1 and above as well as Unicode.

The Tightrope Walk: Avoiding Reserved Words

Your variable names must dodge JavaScript's reserved words. They're like VIPs, having their dedicated privileges within the language, and any misuse can generate surprising errors. And though the ECMAScript standard specifies a minimum identifier length, rest assured, most browsers can handle much more than necessary.

Creativity Awaits: Crafting Unique Variable Names

JavaScript offers a playground for creative coding. Whether you're integrating with an extension library, catering to an international audience, or striving for forward compatibility, its flexible naming conventions give you vast freedom.

Longevity Matters: Future-proofing your code

Choosing a symbol for your library warrants long-term thinking. Will it gel well with other popular libraries? Is it extendable? Anticipating potential integrations with upcoming libraries can help future-proof your work.

Power to Please: The Magic of Single Characters

Single-character symbols bring simplicity, and they shine when it comes to extension libraries. They're easy to remember, quick to type but tread carefully: ensure they're unique and pose no conflict.