Sunday, August 19, 2018

ES 6 features - New String methods| Learn Es6 tutorials

ES6 Features String methods

Es6 introduced new methods of a String object. In this blog post, I will cover the new string methods with examples
Newly introduced String methods can be generic and Unicode methods
Generic methods
  • startsWith()
  • endsWith()
  • includes()
  • repeat()

String.prototype.startsWith() method example

startsWith() method returns 
true - if the passed string with search string is matched from the starting index position, If index position is specified, It checks at the nth position 
false - search string is not matched
Syntax
startsWith(searchstring,index)
The two arguments are
1. String to search -  substring to be searched
2. Index position - It is a position on which search starts from. By default is zero
const message = "This is a new string methods";
console.log(message.startsWith("This is")); // true
console.log(message.startsWith("Thias is")); // false
console.log(message.startsWith("is", 4)); // false
console.log(message.startsWith("is", 5)); // true

String.prototype.endsWith() method example

endsWith() method also  take two arguments
This method returns true if string end is matched with other string
Syntax
endsWith(searchstring,index)
It has two arguments
1.Search string - string to search that matched from end
2. Index position - It is a position to match with string, this is optional
const message = "This is a new string methods";
console.log(message.endsWith("methods")); // true
console.log(message.endsWith("methodsa is")); // false
console.log(message.endsWith("is", 4)); // true
console.log(message.endsWith("is", 5)); // false

String.prototype.includes() method example

This return true if the search substring contains in a string
includes(searchstring,index)
It has two arguments
1.Search string - string to be matched with given string
2. Index position - It is starting position to begin searching the string, This is optional
const message = "this is tesing include";

console.log(message.includes("tesing")); // true
console.log(message.includes("adfadf")); // false
console.log(message.includes("is", 8)); // false
console.log(message.includes("is", 2)); // true

String.prototype.repeat() method example

This method repeats the given string for given number times.
It gives the output concatenate strings
str.repeat(count)
parameter - the number of times to repeat the string
const message = "cloud";
console.log(message.repeat(2)); // cloudcloud
console.log(message.repeat(3)); // cloudcloudcloud

Unicode methods

es6 introduced methods for dealing with Unicode strings.
Here are the methods for
String.fromCodePoint
String.prototype.codePointAt;
String.prototype.normalize;

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