StringsMethods

 string : String is a primitive data type in JavaScript. A string is textual content. 
          It must be enclosed in single or double quotation marks.
          Since, string is character index, it can be accessed using for loop and for-of loop.
 ( A JavaScript string is zero or more characters written inside quotes. )
 Example
 var name = "Ganesh";
 Result :
 "Ganesh"

 String Length : To find the length of a string, use the built-in length property
 Example 
 var numbers = "123456789";
 number.length;  
 Result :
 9

 Strings Can be Objects :
 Normally, JavaScript strings are primitive values, created from literals:
 let a = "Ganesh";
 But strings can also be defined as objects with the keyword new:
 let b = new String("Ganesh");
 Result :
 typeof a  
 'String'
 typeof b 
 'object'
 
 JavaScript methods for searching strings:
  1.String.indexOf()
  2.String.lastIndexOf()
  3.String.startsWith()
  4.String.endsWith()

String.indexOf() : The indexOf() method returns the index of (the position of) the first occurrence of a specified text in a string.
   Note : JavaScript counts positions from zero.
   0 is the first position in a string, 1 is the second, 2 is the third ...
  Example 
  var str = "HELLO EVERY ONE";
  str.indexOf("EVERY");
  Result :
  6
  
String.lastIndexOf() : The lastIndexOf() method returns the index of the last occurrence of a specified text in a string.
  Example
  let str = "HELLO EVERY ONE";
  str.lastIndexOf("ONE");
  Result :
  12
String.search() : The search() method searches a string for a specified value and returns the position of the match:
  Example
  let example = "I LOVE WEB SERIES";
  example.search("SERIES"):
  Result :
  11
  
Extracting String Parts
There are 3 methods for extracting a part of a string:
 1.slice(start, end)
 2.substring(start, end)
 3.substr(start, length)
 
 slice() : slice() extracts a part of a string and returns the extracted part in a new string.
   The method takes 2 parameters: the start position, and the end position (end not included).
   Note : JavaScript counts positions from zero. First position is 0 .
   Example
   let names = "Ganesh, Mahesh, Suresh";
   names.slice(8, 14);
   Result :
   Mahesh
   If a parameter is negative, the position is counted from the end of the string.
   Example
   let x = "Ganesh, Mahesh, Suresh";
   x.slice(-22, -8);
   Result :
   'Ganesh, Mahesh'
   
 substring() : The difference is that substring() cannot accept negative indexes.
  substring() is similar to slice().
  Example
  let str = "Apple, Banana, Kiwi";
  str.substr(0,13);
  Result :
  'Apple, Banana'
  
 replace() : The replace() method replaces a specified value with another value in a string.
  Example 1 :
  let text = "Please visit Microsoft!";
  text.replace("Microsoft", "W3Schools");
  Result : 
  'Please visit W3Schools!'
  To replace case insensitive, use a regular expression with an /i flag (insensitive):
   Example 2 :
   let text = "Please visit Microsoft!";
   text.replace(/MICROSOFT/i, "W3Schools");
   Result : 
   'Please visit W3Schools!'
   Note : that regular expressions are written without quotes.
  To replace all matches, use a regular expression with a /g flag (global match):
   Example 3 :
   let text = "Please visit Microsoft and Microsoft!";
   let newText = text.replace(/Microsoft/g, "W3Schools");
   Result : 
   'Please visit W3Schools and W3Schools!'
   
  toUpperCase() : A string is converted to upper case with toUpperCase()
   Example
   let text1 = "Hello , Hii!";       
   let text2 = text1.toUpperCase();
   Result :
   'HELLO , HII!'
   
  toLowerCase() : A string is converted to lower case with toLowerCase()
   Example
   let text1 = "Hello World!";       
   text1.toLowerCase();
   Result : 
   'hello world!'
   
 concat() : concat() joins two or more strings:
  Example 1 :
  let text1 = "Hello";
  let text2 = "World";
  text1.concat(" ", text2);
  Result : 
  'Hello World'
 The concat() method can be used instead of the plus operator. These two lines do the same:
  Example 2 :
  text = "Hello" + " " + "World!";
  text = "Hello".concat(" ", "World!");
  Result : 
  'Hello World!'
 NOTE : All string methods return a new string. They don't modify the original string.
        Formally said: Strings are immutable: Strings cannot be changed, only replaced.
        
trim() : The trim() method removes whitespace from both sides of a string.
  Example
  let text = "       Hello World!        ";
  text.trim() 
  Result :
  'Hello World!'
  
charAt() : The charAt() method returns the character at a specified index (position) in a string.
  Example
  let text = "CULTMIND";
  text.charAt(1)
  Result : 
  'U'