String like string javascript

JavaScript string

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:

let str = 'Hi'; let greeting = "Hello";Code language: JavaScript (javascript)

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

let name = `John`';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:

let mesage = `"I'm good". She said";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:

let name = 'John'; let message = `Hi, I'm $ .`; console.log(message);Code language: JavaScript (javascript)

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:

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

let str = 'I\'m a string!';Code language: JavaScript (javascript)

Getting the length of the string

The length property returns the length of a string:

let str = "Good Morning!"; console.log(str.length); // 13Code 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:

let str = "Hello"; console.log(str[0]); // "H"Code language: JavaScript (javascript)

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

let str = "Hello"; console.log(str[str.length -1]); // "o"Code language: JavaScript (javascript)

Concatenating strings via + operator

let name = 'John'; let str = 'Hello ' + name; console.log(str); // "Hello John"Code language: JavaScript (javascript)

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

let className = 'btn'; className += ' btn-primary' className += ' none'; console.log(className);Code language: JavaScript (javascript)

btn btn-primary noneCode language: JavaScript (javascript)

Converting values to string

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

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:

let status = false; let str = status.toString(); // "false" let back = Boolean(str); // trueCode language: JavaScript (javascript)

• 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

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:

let result = 'a' < 'b'; console.log(result); // trueCode language: JavaScript (javascript)

let result = 'a' < 'B'; console.log(result); // falseCode 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 `>, >=,

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JavaScript String Reference

A JavaScript string stores a series of characters like «John Doe».

A string can be any text inside double or single quotes:

String indexes are zero-based:

The first character is in position 0, the second in 1, and so on.

For a tutorial about Strings, read our JavaScript String Tutorial.

String Properties and Methods

Normally, strings like «John Doe», cannot have methods or properties because they are not objects.

But with JavaScript, methods and properties are also available to strings, because JavaScript treats strings as objects when executing methods and properties.

JavaScript String Methods

Name	Description
charAt()	Returns the character at a specified index (position)
charCodeAt()	Returns the Unicode of the character at a specified index
concat()	Returns two or more joined strings
constructor	Returns the string’s constructor function
endsWith()	Returns if a string ends with a specified value
fromCharCode()	Returns Unicode values as characters
includes()	Returns if a string contains a specified value
indexOf()	Returns the index (position) of the first occurrence of a value in a string
lastIndexOf()	Returns the index (position) of the last occurrence of a value in a string
length	Returns the length of a string
localeCompare()	Compares two strings in the current locale
match()	Searches a string for a value, or a regular expression, and returns the matches
prototype	Allows you to add properties and methods to an object
repeat()	Returns a new string with a number of copies of a string
replace()	Searches a string for a pattern, and returns a string where the first match is replaced
replaceAll()	Searches a string for a pattern and returns a new string where all matches are replaced
search()	Searches a string for a value, or regular expression, and returns the index (position) of the match
slice()	Extracts a part of a string and returns a new string
split()	Splits a string into an array of substrings
startsWith()	Checks whether a string begins with specified characters
substr()	Extracts a number of characters from a string, from a start index (position)
substring()	Extracts characters from a string, between two specified indices (positions)
toLocaleLowerCase()	Returns a string converted to lowercase letters, using the host’s locale
toLocaleUpperCase()	Returns a string converted to uppercase letters, using the host’s locale
toLowerCase()	Returns a string converted to lowercase letters
toString()	Returns a string or a string object as a string
toUpperCase()	Returns a string converted to uppercase letters
trim()	Returns a string with removed whitespaces
trimEnd()	Returns a string with removed whitespaces from the end
trimStart()	Returns a string with removed whitespaces from the start
valueOf()	Returns the primitive value of a string or a string object

Note

All string methods return a new value.

They do not change the original variable.

String HTML Wrapper Methods

HTML wrapper methods return a string wrapped inside an HTML tag.

These are not standard methods, and may not work as expected.

Method	Description
anchor()	Displays a string as an anchor
big()	Displays a string using a big font
blink()	Displays a blinking string
bold()	Displays a string in bold
fixed()	Displays a string using a fixed-pitch font
fontcolor()	Displays a string using a specified color
fontsize()	Displays a string using a specified size
italics()	Displays a string in italic
link()	Displays a string as a hyperlink
small()	Displays a string using a small font
strike()	Displays a string with a strikethrough
sub()	Displays a string as subscript text
sup()	Displays a string as superscript text

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