JavaScript String Methods
JavaScript provides a variety of built-in methods to work with strings — allowing you to extract, modify, search, and format text with ease. Below are some of the most commonly used core string methods:
slice()
slice() extracts a part of the string based on the given stating-index and ending-index and returns a new string.
// Define a string variable
let A = 'Geeks for Geeks';
// Use the slice() method to extract a substring
let b = A.slice(0, 5);
let c = A.slice(6, 9);
let d = A.slice(10);
// Output the value of variable
console.log(b);
console.log(c);
console.log(d);
// Define a string variable
let A = 'Geeks for Geeks';
// Use the slice() method to extract a substring
let b = A.slice(0, 5);
let c = A.slice(6, 9);
let d = A.slice(10);
// Output the value of variable
console.log(b);
console.log(c);
console.log(d);
Output
Geeks for Geeks
substring()
substring() returns the part of the given string from the start index to the end index. Indexing starts from zero (0).
// Define a string variable
let str = "Mind, Power, Soul";
// Use the substring() method to extract a substring
let part = str.substring(6, 11);
// Output the value of variable
console.log(part);
// Define a string variable
let str = "Mind, Power, Soul";
// Use the substring() method to extract a substring
let part = str.substring(6, 11);
// Output the value of variable
console.log(part);
Output
Power
substr()
substr() This method returns the specified number of characters from the specified index from the given string. It extracts a part of the original string.
// Define a string variable 'str'
let str = "Mind, Power, Soul";
// Use the substr() method to extract a substring f
let part = str.substr(6, 5);
// Output the value of variable
console.log(part);
// Define a string variable 'str'
let str = "Mind, Power, Soul";
// Use the substr() method to extract a substring f
let part = str.substr(6, 5);
// Output the value of variable
console.log(part);
Output
Power
replace()
replace() replaces a part of the given string with another string or a regular expression. The original string will remain unchanged.
// Define a string variable 'str'
let str = "Mind, Power, Soul";
// Use the replace() method to replace the substring
let part = str.replace("Power", "Space");
// Output the resulting string after replacement
console.log(part);
// Define a string variable 'str'
let str = "Mind, Power, Soul";
// Use the replace() method to replace the substring
let part = str.replace("Power", "Space");
// Output the resulting string after replacement
console.log(part);
Output
Mind, Space, Soul
replaceAll()
replaceAll() returns a new string after replacing all the matches of a string with a specified string or a regular expression. The original string is left unchanged after this operation.
// Define a string variable 'str'
let str = "Mind, Power, Power, Soul";
// Use the replaceAll() method to replace all occurrences
//of "Power" with "Space" in the string 'str'
let part = str.replaceAll("Power", "Space");
// Output the resulting string after replacement
console.log(part);
// Define a string variable 'str'
let str = "Mind, Power, Power, Soul";
// Use the replaceAll() method to replace all occurrences
//of "Power" with "Space" in the string 'str'
let part = str.replaceAll("Power", "Space");
// Output the resulting string after replacement
console.log(part);
Output
Mind, Space, Space, Soul
toUpperCase()
toUpperCase() converts all the characters present in the String to upper case and returns a new String with all characters in upper case. This method accepts single parameter stringVariable string that you want to convert in upper case.
// Define a string variable
let gfg = 'GFG ';
// Define another string variable
let geeks = 'stands-for-GeeksforGeeks';
// Convert the string 'geeks' to uppercase using the toUpperCase() method
console.log(geeks.toUpperCase());
// Define a string variable
let gfg = 'GFG ';
// Define another string variable
let geeks = 'stands-for-GeeksforGeeks';
// Convert the string 'geeks' to uppercase using the toUpperCase() method
console.log(geeks.toUpperCase());
Output
STANDS-FOR-GEEKSFORGEEKS
toLowerCase()
toLowerCase() converts all the characters present in the so lowercase and returns a new string with all the characters in lowercase.
// Define a string variable
let gfg = 'GFG ';
// Define a string variable
let geeks = 'stands-for-GeeksforGeeks';
// Convert the string 'geeks' to lowercase using the toLowerCase() method
console.log(geeks.toLowerCase());
// Define a string variable
let gfg = 'GFG ';
// Define a string variable
let geeks = 'stands-for-GeeksforGeeks';
// Convert the string 'geeks' to lowercase using the toLowerCase() method
console.log(geeks.toLowerCase());
Output
stands-for-geeksforgeeks
concat()
concat() combines the text of two strings and returns a new combined or joined string. To concatenate two strings, we use the concat() method on one object of string and send another object of string as a parameter. This method accepts one argument. The variable contains text in double quotes or single quotes.
let gfg = 'GFG ';
let geeks = 'stands for GeeksforGeeks';
// Accessing concat method on an object
// of String passing another object
// as a parameter
console.log(gfg.concat(geeks));
let gfg = 'GFG ';
let geeks = 'stands for GeeksforGeeks';
// Accessing concat method on an object
// of String passing another object
// as a parameter
console.log(gfg.concat(geeks));
Output
GFG stands for GeeksforGeeks
trim()
trim() is used to remove either white spaces from the given string. This method returns a new string with removed white spaces. This method is called on a String object. This method doesn't accept any parameter.
let gfg = 'GFG ';
let geeks = 'stands-for-GeeksforGeeks';
// Storing new object of string
// with removed white spaces
let newGfg = gfg.trim();
// Old length
console.log(gfg.length);
// New length
console.log(newGfg.length)
let gfg = 'GFG ';
let geeks = 'stands-for-GeeksforGeeks';
// Storing new object of string
// with removed white spaces
let newGfg = gfg.trim();
// Old length
console.log(gfg.length);
// New length
console.log(newGfg.length)
Output
7 3
trimStart()
trimStart() removes whitespace from the beginning of a string. The value of the string is not modified in any manner, including any whitespace present after the string.
// Define a string variable
let str = " Soul";
// Output the original value of the string
console.log(str);
// Use the trimStart() method to remove leading whitespace from the string 'str'
let part = str.trimStart();
// Output the resulting string after removing leading whitespace
console.log(part);
// Define a string variable
let str = " Soul";
// Output the original value of the string
console.log(str);
// Use the trimStart() method to remove leading whitespace from the string 'str'
let part = str.trimStart();
// Output the resulting string after removing leading whitespace
console.log(part);
Output
Soul Soul
trimEnd()
trimEnd() removes white space from the end of a string. The value of the string is not modified in any manner, including any white-space present before the string.
// Define a string variable
let str = "Soul ";
// Output the original value of the string 'str'
console.log(str);
// Use the trimEnd() method to remove trailing whitespace from the string 'str'
let part = str.trimEnd();
// Output the resulting string after removing trailing whitespace
console.log(part);
// Define a string variable
let str = "Soul ";
// Output the original value of the string 'str'
console.log(str);
// Use the trimEnd() method to remove trailing whitespace from the string 'str'
let part = str.trimEnd();
// Output the resulting string after removing trailing whitespace
console.log(part);
Output
Soul Soul
padStart()
padStart() pad a string with another string until it reaches the given length. The padding is applied from the left end of the string.
// Define a string variable
let stone = "Soul";
// Use the padStart() method to add padding characters "Mind "
//to the beginning of the string 'stone'
stone = stone.padStart(9, "Mind ");
// Output the resulting string after padding
console.log(stone);
// Define a string variable
let stone = "Soul";
// Use the padStart() method to add padding characters "Mind "
//to the beginning of the string 'stone'
stone = stone.padStart(9, "Mind ");
// Output the resulting string after padding
console.log(stone);
Output
Mind Soul
padEnd()
padEnd() pad a string with another string until it reaches the given length. The padding is applied from the right end of the string.
// Define a string variable
let stone = "Soul";
// Use the padEnd() method to add padding characters
//" Power" to the end of the string 'stone'
stone = stone.padEnd(10, " Power");
// Output the resulting string after padding
console.log(stone);
// Define a string variable
let stone = "Soul";
// Use the padEnd() method to add padding characters
//" Power" to the end of the string 'stone'
stone = stone.padEnd(10, " Power");
// Output the resulting string after padding
console.log(stone);
Output
Soul Power
charAt()
charAt() returns the character at the specified index. String in JavaScript has zero-based indexing.
let gfg = 'GeeksforGeeks';
let geeks = 'GfG is the best platform to learn and\n'+
'experience Computer Science.';
// Print the string as it is
console.log(gfg);
console.log(geeks);
// As string index starts from zero
// It will return first character of string
console.log(gfg.charAt(0));
console.log(geeks.charAt(5));
let gfg = 'GeeksforGeeks';
let geeks = 'GfG is the best platform to learn and\n'+
'experience Computer Science.';
// Print the string as it is
console.log(gfg);
console.log(geeks);
// As string index starts from zero
// It will return first character of string
console.log(gfg.charAt(0));
console.log(geeks.charAt(5));
Output
GeeksforGeeks GfG is the best platform to learn and experience Computer Science. G s
charCodeAt()
charCodeAt() returns a number that represents the Unicode value of the character at the specified index. This method accepts one argument.
let gfg = 'GeeksforGeeks';
let geeks = 'GfG is the best platform\n\
to learn and experience\n\
Computer Science.';
// Return a number indicating Unicode
// value of character at index 0 ('G')
console.log(gfg.charCodeAt(0));
console.log(geeks.charCodeAt(5));
let gfg = 'GeeksforGeeks';
let geeks = 'GfG is the best platform\n\
to learn and experience\n\
Computer Science.';
// Return a number indicating Unicode
// value of character at index 0 ('G')
console.log(gfg.charCodeAt(0));
console.log(geeks.charCodeAt(5));
Output
71 115
split()
split() splits the string into an array of sub-strings. This method returns an array. This method accepts a single parameter character on which you want to split the string.
let gfg = 'GFG '
let geeks = 'stands-for-GeeksforGeeks'
// Split string on '-'.
console.log(geeks.split('-'))
let gfg = 'GFG '
let geeks = 'stands-for-GeeksforGeeks'
// Split string on '-'.
console.log(geeks.split('-'))
Output
[ 'stands', 'for', 'GeeksforGeeks' ]
More JS String Methods
Below is the JavaScript string functions list:
Instance Methods | Description |
---|---|
at() | Find the character at the specified index. |
anchor() | Creates an anchor element that is used as a hypertext target. |
charAt() | Returns that character at the given index of the string. |
charCodeAt() | Returns a Unicode character set code unit of the character present at the index in the string. |
codePointAt() | Return a non-negative integer value i.e, the code point value of the specified element. |
concat() | Join two or more strings together in JavaScript. |
endsWith() | Whether the given string ends with the characters of the specified string or not. |
includes() | Returns true if the string contains the characters, otherwise, it returns false. |
indexOf() | Finds the index of the first occurrence of the argument string in the given string. |
lastIndexOf() | Finds the index of the last occurrence of the argument string in the given string. |
localeCompare() | Compare any two elements and returns a positive number |
match() | Search a string for a match against any regular expression. |
matchAll() | Return all the iterators matching the reference string against a regular expression. |
normalize() | Return a Unicode normalization form of a given input string. |
padEnd() | Pad a string with another string until it reaches the given length from rightend. |
padStart() | Pad a string with another string until it reaches the given length from leftend. |
repeat() | Build a new string containing a specified number of copies of the string. |
replace() | Replace a part of the given string with some another string or a regular expression |
replaceAll() | Returns a new string after replacing all the matches of a string with a specified string/regex. |
search() | Search for a match in between regular expressions and a given string object. |
slice() | Return a part or slice of the given input string. |
split() | Separate given string into substrings using a specified separator provided in the argument. |
startsWith() | Check whether the given string starts with the characters of the specified string or not. |
substr() | Returns the specified number of characters from the specified index from the given string. |
substring() | Return the part of the given string from the start index to the end index. |
toLowerCase() | Converts the entire string to lowercase. |
toLocaleLowerCase() | Returns the calling string value converted to a lowercase letter. |
toLocaleUpperCase() | Returns the calling string value converted to a uppercase letter. |
toUpperCase() | Converts the entire string to uppercase. |
toString() | Return the given string itself. |
trim() | Remove the white spaces from both ends of the given string. |
trimEnd() | Remove white space from the end of a string. |
trimStart() | Remove white space from the start of a string. |
valueOf() | Return the value of the given string. |
string[Symbol.iterator]() | This method is used to make String iterable. [@@iterator]() returns an iterator object which iterates over all code points of the String. |
fromCharCode(n1, n2, ..., nX) | This method is used to create a string from the given sequence of UTF-16 code units. This method returns a string, not a string object. |
fromCodePoint(a1, a2, a3, ....) | This method in JavaScript that is used to return a string or an element for the given sequence of code point values (ASCII value). |
isWellFormed() | This method is used to check if the string contains a lone surrogate or not |
String.raw(str, ...sub) | This is a static method that is used to get the raw string form of template literals. These strings do not process escape characters. |
toWellFormed() | This method is used to return where all lone surrogates of this string are replaced with the Unicode replacement character. |
Also Check
- JavaScript String constructor Property
- JavaScript Strings Tutorial
- JavaScript String length Property
- JavaScript String Programming Examples