JavaScript string holds primitive type values which is a sequence of characters. JavaScript treats primitive values as objects when executing methods and properties.
Strings can be created as primitives, from string literals, or as objects, using the String() constructor:
//string literal
const str= "A string primitive";
//string object (using new keyword)
const str= new String("A String object");
So, JavaScript string Object methods and properties (length, substring(), etc). To find the length of a string, use the built-in length property:
Creating Strings:
You can create strings using single or double quotes, or you can use the String constructor:
let str1 = "Hello, World!";
let str2 = 'JavaScript';
let str3 = new String("This is a String Object");
Properties:
length: Returns the length (number of characters) of the string.
let text = "Hello, World!";
console.log(text.length); // Outputs 13
JavaScript string examples
Simple example code strings are created by surrounding them with quotes.
<!DOCTYPE html>
<html>
<body>
<script>
const n1 = 'Mike';
const n2 = "Jack";
const res = `The names are ${n1} and ${n2}`;
console.log(typeof(res))
console.log(res)
</script>
</body>
</html> Output:
Single and double quotes are practically the same, and you can use either.
Backticks are generally used when you need to include variables or expressions into a string. This is done by wrapping variables or expressions with ${variable or expression} as shown above.
The string cannot be changed
You can’t change the strings because JavaScript strings are immutable.
let a = 'hello';
a[0] = 'H';
console.log(a); // "hello"But you can assign the variable name to a new string.
let a = 'hello';
a = 'Hello';
console.log(a); // "Hello"Multiline Strings
Use the + operator or the \ operator to get the multiline string.
// using the + operator
const message1 = 'This is a long message ' +
'that spans across multiple lines' +
'in the code.'
// using the \ operator
const message2 = 'This is a long message \
that spans across multiple lines \
in the code.'JavaScript String Methods
| Method | Description |
|---|---|
| charAt(index) | returns the character at the specified index |
| concat() | joins two or more strings |
| replace() | replaces a string with another string |
| split() | converts the string to an array of strings |
| substr(start, length) | returns a part of a string |
| substring(start,end) | returns a part of a string |
| slice(start, end) | returns a part of a string |
| toLowerCase() | returns the passed string in lower case |
| toUpperCase() | returns the passed string in upper case |
| trim() | removes whitespace from the strings |
| includes() | searches for a string and returns a boolean value |
| search() | searches for a string and returns a position of a match |
Do comment if you have any doubts or suggestions on this Js string topic.
Note: The All JS Examples codes are tested on the Firefox browser and the Chrome browser.
OS: Windows 10
Code: HTML 5 Version