10 JavaScript String Methods

   10 JavaScript String Methods to Know:

1. startsWith()
Check if string starts with specified character(s).
 

    const s__1 = 'JavaScript is amazing';
   
   console.log(s__1.startsWith('JavaScript')); //true
   console.log(s__1.startsWith('Java')); //true
   console.log(s__1.startsWith('javascript')); //false


   // position is optional
   // if not specified, the default value is 0
   console.log(s__1.startsWith('Script', 4)); //true
   console.log(s__1.startsWith('SCRIPT', 4)); //false

2. endsWith()
Check if string ends with specified character(s).
 

    const s__2 = 'JavaScript is amazing';
  
   // check if ends with 'amazing'
   console.log(s__2.endsWith('amazing')); //true
   console.log(s__2.endsWith('ing')); //true
   console.log(s__2.endsWith('Amazing')); //false

  
   // length is optional
   // if not specified, the default value is length of the string
   console.log(s__2.endsWith('is', 13)); //true
   console.log(s__2.endsWith('i', 13)); //false
   console.log(s__2.endsWith('s', 13)); //true

3. includes()
Check if string contains specified character(s).
 

    const s__3 = 'JavaScript is amazing';

   console.log(s__3.includes('Script')); //true
   console.log(s__3.includes('script')); //false
   console.log(s__3.includes(' ')); //true
   console.log(s__3.includes('array')); //false

4. slice()
Copy some part of string without modifying the original one.

    const s__4 = 'JavaScript is amazing';

   // Default start index is 0
   console.log(s__4.slice()); // 'JavaScript is amazing'
  
   // start copy at index 4
   console.log(s__4.slice(4)); // 'Script is amazing'

   // end copy at index 10 (character at this index will not be included)
   console.log(s__4.slice(0, 10)); // 'JavaScript'

5. toUpperCase()
Convert string into upper case.
 

    const s__5 = 'JavaScript is amazing';

   console.log(s__5.toUpperCase()); // 'JAVASCRIPT IS AMAZING'

6. toLowerCase()
Convert string into lower case.
 

    const s__6 = 'JavaScript is amazing';

   console.log(s__6.toLowerCase()); // 'javascript is amazing'

7. charAt()
Return character at specified position.
 

    const s__7 = 'JavaScript is amazing';

   console.log(s__7.charAt()); // 'J'
   console.log(s__7.charAt(11)); // 'i'
   console.log(s__7.charAt(4)); // 'S'
   console.log(s__7.charAt(24)); //''

8. split()
Split string into array of substrings.
 

    const s__8 = 'JavaScript is amazing';
 const s__8New = 'JavaScript-is-amazing';
 
 console.log(s__8.split()); // ["JavaScript is amazing"]


 // Separator string used to determine where to make each split:
 console.log(s__8.split('S')); // ["Java", "cript is amazing"]
 console.log(s__8.split('is')); // ["JavaScript ", " amazing"]
 console.log(s__8.split(' ')); // ["JavaScript", "is", "amazing"]
 console.log(s__8New.split('-')); // ["JavaScript", "is", "amazing"]

9. replace()
Replaces specified value with another value in a string.
 

    const s__9 = 'JavaScript is amazing';

 console.log(s__9.replace('JavaScript', 'Node.js')); // 'Node.js is amazing'


 // replace() method is case sensitive
 // replace will not work
 console.log(s__9.replace('Javascript', 'Node.js')); // 'JavaScript is amazing'


 // use regular expression for case insesitive
 console.log(s__9.replace(/Javascript/i, 'Node.js')); // 'Node.js is amazing'


 // replace() method replaces only the first match
 console.log(s__9.replace('a', 'A')); // 'JAvaScript is amazing'


 // to replace all matches, use regular expression
 console.log(s__9.replace(/a/g, 'A')); // 'JAvAScript is AmAzing'

10. repeat()
Return new string with specified number of copies of existing string.
 

    const str = 'JavaScript';

   console.log(str.repeat(3)); // 'JavaScriptJavaScriptJavaScript'
   console.log(str.repeat(1)); // 'JavaScript'
   console.log(str.repeat(0)); // ''

     HappyLearning!:) by_@boolean_maybe