JavaScript String Methods

 JavaScript String Methods Cheat Sheet

javascript string methods cheat sheet

1} charAt()

• The charAt() method returns the character at a specified index in a string.
• The index of the first character is 0, the second character is 1, and so on.
• Example:

var str = 'Bhavesh Ajani';
console.log(str.charAt(0));
//Output: B

2} concat()

• The concat() method joins two or more strings.
• concat() does not change the existing strings, but returns a new string.
• Example:

var strA = 'Bhavesh';
var strB = 'Ajani';
console.log(strA.concat(strB));
//Output: BhaveshAjani

3} indexOf()

• The indexOf() method returns the position of the first occurrence of a specified value in a string.
• indexOf() returns -1 if the value is not found.
• indexOf() is case sensitive.
• Example:

var str = 'Bhavesh';
console.log(str.indexOf('B'));
//Output: 0
console.log(str.indexOf('b'));
//Output: -1

4} lastIndexOf()

• The lastIndexOf() method returns the position of the last occurrence of a specified value in a string.
• lastIndexOf() searches the string from the end to the beginning.
• lastIndexOf() returns -1 if the value is not found.
• lastIndexOf() is case sensitive.
• Example:

var str = 'Bhavesh Ajani';
console.log(str.lastIndexOf('a'));
//Output: 10
console.log(str.lastIndexOf('A'));
//Output: 8		
console.log(str.lastIndexOf('z'));
//Output: -1	

5} replace()

• The replace() method searches a string for a specified value, or a regular expression, and returns a new string where the specified values are replaced.
• replace() does not change the original string.
• Example:

var str = 'Bhavesh Adani';
console.log(str.replace('Adani', 'Ajani'));
//Output: Bhavesh Ajani

6} search()

• The search() method searches a string for a specified value, and returns the position of the match.
• The search value can be string or a regular expression.
• The search() method returns -1 if no match is found.
• Example:

var str = 'Bhavesh Ajani';	
console.log(str.search('Ajani'));		
//Output: 8
console.log(str.search('Adani'));		
//Output: -1

7} slice(start,end)

• The slice() method extracts parts of a string and returns the extracted parts in a new string.
• Use the start and end parameters to specify the part of the string you want to extract.
• The first character has the position 0, the second has position 1, and so on.
• Use a negative number to select from the end of the string.
• the end position does not include, it extracts strings like end_position - 1.
• Example:

var str = 'Bhavesh Ajani';
console.log(str.slice(0, 7));
//Output: Bhavesh

8} substr(start,length)

• The substr() method extracts parts of a string, beginning at the character at a specified position, and returns a specified number of characters.
• If you extract characters from the end of the string, use a negative start number.
• substr() method does not change the original string.
• Example:

var str = 'Bhavesh Ajani';
console.log(str.substr(0, 9));
//Output: Bhavesh A

9} substring(start,end)

• The substring() method extracts characters between "start" and "end", not including "end".
• The substring() method does not change the original string.
• Example:

var str = 'Bhavesh Ajani';
console.log(str.substring(0, 7));
//Output: Bhavesh

10} toUpperCase()

• The toUpperCase() method converts a string to uppercase letters.
• The toUpperCase() method does not change the original string.
• Example:

var str = 'Bhavesh Ajani';
console.log(str.toUpperCase());
//Output: BHAVESH AJANI

11} valueOf()

• The valueOf() method returns the value of a string.
• It is used to return the primitive value of a number.
• Example:

var str = 'Bhavesh Ajani';
console.log(str.valueOf());
//Output: Bhavesh Ajani

12} trim()

• The trim() method removes whitespace from both sides of a string.
• The trim() method does not change the original string.
• Example:

var str = ' Bhavesh Ajani ';
console.log(str.trim());
//Output: Bhavesh Ajani

13} toString()

• The toString() method returns the value of a string.
• The toString() method converts a number to a string.
• Example:

var str = 7;
console.log(str.toString());
//Output: 7

14} includes()

• The includes() method returns true if a string contains a specified string, otherwise false.
• includes() method determines whether a string contains the given characters within it or not.
• includes() is case sensitive.
• Example:

var str = 'Bhavesh Ajani';
console.log(str.includes('ajani'));
//Output: false
console.log(str.includes('Ajani'));
//Output: true

15} charCodeAt()

• The charCodeAt() method returns the Unicode of the character at the specified index in a string.
• The index of the first character is 0, the second character 1, and so on.
• The charCodeAt() method returns an integer between 0 and 65535 representing the UTF-16 code unit at the given index.
• Example:

var str = 'Bhavesh Ajani';
console.log(str.charCodeAt(2));
//Output: 97
console.log(str.charCodeAt(0));
//Output: 66

16} match()

• The match() method searches a string for a match against a regular expression, and returns the matches, as an Array object.
• This method returns null if no match is found.
• Example:

var str = 'Bhavesh Ajani AJANI';
console.log(str.match(/Ajani/g));
//Output: [ 'Ajani' ]

console.log(str.match(/ajani/g));
//Output: null

console.log(str.match(/ni/gi));
//Output: [ 'ni', 'NI' ]

• Here “g” flag indicates that the regular expression should be tested against all possible matches in a string. 

17} split()

• The split() method splits a string into an array of substrings, and returns the new array.
• If an empty string ("") is used as the separator, the string is split between each character.
• The split() method does not change the original string.
• Example:

var strA = '1,2,3,4,5,6,7';
console.log(strA.split(","));
//Output:   [ '1', '2', '3', '4', '5', '6', '7' ]

var strB = 'Bhavesh Ajani';
console.log(strB.split(" "));
//Output:   [ 'Bhavesh', 'Ajani' ]

var strC = 'My Name Is Bhavesh';
console.log(strC.split(" ", 2));
//Output:   [ 'My', 'Name' ]

18} toLowerCase()

• The toLowerCase() method converts a string to lowercase letters.
• The toLowerCase() method does not change the original string.
• Example:

var str = 'Bhavesh Ajani';
console.log(str.toLocaleLowerCase());
//Output:   bhavesh ajani

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