Unicode Character Set

JavaScript supports Unicode character set. We can name identifiers using unicodes. We can also use unicodes in strings and comments.

Unicode in Identifiers

Names of variables, constants or functions are examples of identifiers. We normally give meaningful identifier names in English. Since, JavaScript supports unicode, we can even name variables in non-english language like Japanese.

let フルーツ = "Apple";
console.log(フルーツ); // 'Apple'

In the above code フルーツ stands for fruit in Japanese.

Unicode in Strings and Comments

We can represent almost all languages in the world using unicode. Let us try to print a string literal that contains a non-english language.

Here is an example that prints a text in Malayalam language.

let place = "കോട്ടയം";
console.log(place); // 'കോട്ടയം'

Unicode Escape Sequences

Some computer hardware and software cannot display, input, or correctly process the full set of Unicode characters. For example, if we are using an English keyboard, we cannot input é. In that case, we can use unicode escape sequence to print the é. The escape sequence for é is \u00E9.

console.log("\u00E9"); // 'é'

In ES6, escape sequence with curly brackets(Eg: \u{1F600}) were introduced. It can support more range than the older four character format(\u00E9).

Here is an example of new ES6 syntax that prints a smiley.

console.log("\u{1F600}"); // '😀'

Unicode Normalization

When it comes to some characters like é, it can be represented in multiple ways in JavaScript.

console.log("\u00E9"); // 'é'
console.log("e\u0301"); // 'é'

Even though it looks same for us, for JavaScript they are different. So what is the problem? One problem is, we can redeclare constants that looks like same names.

const é = 10;
const é = 20;
console.log(é); // 10
console.log(é); // 20

Are you finding the above code weird? Yes. You can copy the above code and try if it works.

Inorder to avoid such ambiguities, we need to normalize coding either in the editor or using an external tool. JavaScript cannot do any normalization on its own.