Summary: in this tutorial, you’ll learn about the JavaScript string primitive type and how to use it to define strings.

Introduction to the JavaScript strings

JavaScript strings are primitive values. Also, strings are immutable. It means that if you modify a string, you will always get a new string. The original string doesn’t change.

To create literal strings, you use either single quotes (') or double quotes (") like this:

Code language: JavaScript (javascript)

ES6 introduced template literals that allow you to define a string backtick (`) characters:

Code language: JavaScript (javascript)

The template literals allow you to use the single quotes and double quotes inside a string without the need of escaping them. For example:

Code language: JavaScript (javascript)

Also, you can place the variables and expressions inside a template literal. JavaScript will replace the variables with their value in the string. This is called string interpolation. For example:

Code language: JavaScript (javascript)

Output:

In this example, JavaScript replaces the name variable with its value inside the template literal.

Escaping special characters

To escape special characters, you use the backslash \ character. For example:

• Windows line break: '\r\n'
• Unix line break: '\n'
• Tab: '\t'
• Backslash '\'

The following example uses the backslash character to escape the single quote character in a string:

Code language: JavaScript (javascript)

Getting the length of the string

The length property returns the length of a string:

Code language: JavaScript (javascript)

Note that JavaScript has the String type (with the letter S in uppercase), which is the primitive wrapper type of the primitive string type. Therefore, you can access all properties and methods of the String type from a primitive string.

Accessing characters

To access the characters in a string, you use the array-like [] notation with the zero-based index. The following example returns the first character of a string with the index zero:

Code language: JavaScript (javascript)

To access the last character of the string, you use the length - 1 index:

Code language: JavaScript (javascript)

Concatenating strings via + operator

To concatenate two or more strings, you use the + operator:

Code language: JavaScript (javascript)

If you want to assemble a string piece by piece, you can use the += operator:

Code language: JavaScript (javascript)

Output:

Code language: JavaScript (javascript)

Converting values to string

To convert a non-string value to a string, you use one of the following:

• String(n);
• ” + n
• n.toString()

Note that the toString() method doesn’t work for undefined and null.

When you convert a string to a boolean, you cannot convert it back. For example:

Code language: JavaScript (javascript)

In this example:

• First, declare the status variable and initialize its with the value of false.
• Second, convert the status variable to a string using the toString() method.
• Third, convert the string back to a boolean value using the Boolean() function. The Boolean() function converts the string "false" to a boolean value. The result is true because "false" is a non-empty string.

Note that only string for which the Boolean() returns false, is the empty string ('');

Comparing strings

To compare two strings, you use comparison operators such as >, >=, <, <=, and == operators.

The comparison operators compare strings based on the numeric values of the characters. And it may return the string order that is different from the one used in dictionaries. For example:

Code language: JavaScript (javascript)

However:

Code language: JavaScript (javascript)

Summary

• JavaScript strings are primitive values and immutable.
• Literal strings are delimited by single quotes ('), double quotes ("), or backticks (`).
• The length property returns the length of the string.
• Use the comparison operators `>, >=, <, <=, == to compare strings.