Javascript String - 25 Methods and 1 Property (Reference)
Javascript
1
In Javascript, strings are objects. Basically, strings are used to store text. It has methods and properties that can be used to manipulate or to get information about the string.
String Methods:
String Properties:
concat()
The concat() method is used to join two or more strings.
var str1 = "Hello ";
var str2 = "world!";
var x = str1.concat(str2);
// Hello world!
// str.concat(str1, str2, ..., strX)
repeat()
The repeat() method is used to repeat a string.
var str = "Hello world!";
var x = str.repeat();
// Hello world!Hello world!
// str.repeat(count)
slice()
The slice() method is used to extract a part of a string and return a new string.
var str = "Hello world!";
var x = str.slice(0, 5);
// Hello
// str.slice(start, end)
replace()
The replace() method is used to replace a part of a string with another string.
var str = "Hello world!";
var x = str.replace("Hello", "Hi");
// Hi world!
// str.replace(searchvalue, newvalue)
charAt()
The charAt() method is used to return the character at the specified index.
var str = "HELLO WORLD";
var x = str.charAt(0);
// H
// str.charAt(index)
charCodeAt()
The charCodeAt() method is used to return the Unicode of the character at the specified index.
var str = "HELLO WORLD";
var n = str.charCodeAt(0);
// 72
// str.charCodeAt(index)
endsWith()
The endsWith() method is used to check whether a string ends with the specified string.
var str = "Hello world!";
var x = str.endsWith("d!");
// true
var str = "Hello world!";
var x = str.endsWith("d!", 3);
// false
// str.endsWith(searchvalue, length)
startsWith()
The startsWith() method is used to check whether a string starts with the specified string.
var str = "Hello world!";
var x = str.startsWith("He");
// true
var str = "Hello world!";
var x = str.startsWith("d!", 3);
// false
// str.startsWith(searchvalue, length)
indexOf()
The indexOf() method is used to find the position of the first occurrence of a specified value in a string.
var str = "Hello world!";
var x = str.indexOf("world");
// 6
var str = "Hello world!";
var x = str.indexOf("world", 8);
// -1
// str.indexOf(searchvalue, start)
lastIndexOf()
The lastIndexOf() method is used to find the position of the last occurrence of a specified value in a string.
var str = "Hello world!";
var x = str.lastIndexOf("world");
// 6
var str = "Hello world!";
var x = str.lastIndexOf("world", 8);
// 6
var str = "Hello world!";
var x = str.lastIndexOf("world", 4);
// -1
// str.lastIndexOf(searchvalue, start)
includes()
The includes() method is used to check whether a string contains the specified string.
var str = "Hello world!";
var x = str.includes("world");
// true
var str = "Hello world!";
var x = str.includes("world", 7);
// false
// str.includes(searchvalue, start)
search()
The search() method is used to search a string for a specified value and return the position of the match.
var str = "Hello world!";
var x = str.search("world");
// 6
// str.search(searchvalue)
match()
The match() method is used to search a string for a specified value and return an array containing the matches.
var str = "Hello world!";
var x = str.match(/o/g);
// 0,0
var str = "Hello world!";
var x = str.match(/xxx/g);
// null
// str.match(regexp)
split()
The split() method is used to split a string into an array of substrings.
var str = "Hello world!";
var x = str.split(" ");
// ["Hello","world!"]
var str = "Hello world!";
var x = str.split(" ", 2);
// ["Hello","world!"]
// str.split(separator, limit)
substr()
The substr() method is used to extract a part of a string.
var str = "Hello world!";
var x = str.substr(1, 4);
// ello
var str = "Hello world!";
var x = str.substr(2);
// llo world!
// str.substr(start, length)
substring()
The substring() method is used to extract a part of a string.
var str = "Hello world!";
var x = str.substring(1, 4);
// ell
var str = "Hello world!";
var x = str.substring(2);
// llo world!
// str.substring(start, length)
toLowerCase()
The toLowerCase() method is used to convert a string to lower case.
var str = "Hello World!";
var x = str.toLowerCase();
// hello world!
toUpperCase()
The toUpperCase() method is used to convert a string to upper case.
var str = "Hello World!";
var x = str.toUpperCase();
// HELLO WORLD!
toLocaleLowerCase()
The toLocaleLowerCase() method is used to convert a string to lower case, according to the host's locale.
var str = "Hello World!";
var x = str.toLowerCase();
// hello world!
toLocaleUpperCase()
The toLocaleUpperCase() method is used to convert a string to upper case, according to the host's locale.
var str = "Hello World!";
var x = str.toUpperCase();
// HELLO WORLD!
trim()
The trim() method is used to remove whitespace from both ends of a string.
var str = " Hello World! ";
var x = str.trim();
// Hello world!
localeCompare()
The localeCompare() method is used to compare two strings in the current locale.
var str1 = "ab";
var str2 = "cd";
var x = str1.localeCompare(str2);
// -1
var str1 = "cd";
var str2 = "ab";
var x = str1.localeCompare(str2);
// 1
var str1 = "ab";
var str2 = "ab";
var x = str1.localeCompare(str2);
// 0
// compare the two strings in the current locale.
// str.localeCompare(compareString)
// Returns -1 if str1 is sorted before str2
// Returns 0 if the two strings are equal
// Returns 1 if str1 is sorted after str2
fromCharCode()
The fromCharCode() method is used to create a string from the specified sequence of Unicode values.
var x = String.fromCharCode(65);
// A
var x = String.fromCharCode(72, 69, 76, 76, 79);
// HELLO
// String.fromCharCode(n1, n2, ..., nX)
toString()
The toString() method is used to convert a string to a string.
var str = "Hello world!";
var x = str.toString();
// Hello world!
valueOf()
The valueOf() method is used to convert a string to a string.
var str = "Hello world!";
var x = str.valueOf();
// Hello world!
length
The length property is a read-only property that contains the number of characters in a string. It is the only built-in property of the String object.
var str = "Hello world!";
var x = str.length;
// 12
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