JavaScript String

Definition and Usage

In JavaScript, a String is a text value. It can hold letters, digits, spaces, and symbols. You write a string with single quotes, double quotes, or backticks: 'Code', "ToFun", or `Hello, ${name}`.

Strings are primitives and they are immutable. Calling toUpperCase() or slice() returns a new string. The value you started with does not change. Join text with + or a template literal. "JS" + 1 becomes the string "JS1", because + concatenates when either side is text.

This page teaches what a String is. The String Methods index and String Properties index list every method and property guide (slice(), includes(), length, and more).

JavaScript Syntax

Common ways to create and inspect strings:

const title = "JavaScript";     // double quotes
const lang = 'JS';               // single quotes
const name = "Ada";
const greet = `Hello, ${name}`;  // template literal
const typed = typeof title;      // "string"
const count = title.length;      // 10
const made = String(42);         // "42"

Core Ideas

Ideas every JavaScript String tutorial builds on:

JavaScript Examples

Three short programs that show how String works in a JS tutorial.

const single = 'Code';
const double = "ToFun";
const name = "Ada";
const greet = `Hello, ${name}`;

console.log(single + double);
console.log(greet);
console.log(typeof greet);

CodeToFun
Hello, Ada
string

let word = "java";
const upper = word.toUpperCase();

console.log(word);
console.log(upper);

word[0] = "J";
console.log(word);

java
JAVA
java

const label = "JS";

console.log(label + 1);
console.log("Hi".length);
console.log("😀".length);
console.log(String(true));

JS1
2
2
true

Next: Methods & Properties Indexes

After you know what a String is, open the indexes for full tutorials on every essential String API in this JavaScript series.

Full lists: String Methods index and String Properties index.