ES6 new method of string

1、String.formCodePoint(Unicode code ) and String.fromCharCode(Unicode code )： take Unicode Code to character
String.fromCodePoint() Can identify greater than 0xffff Code point character , and String.fromCharCode() Cannot identify greater than 0xffff The characters of

String.fromCodePoint(0x20BB7) // '𠮷'
String.fromCharCode(0x20BB7) //  Abandon the highest position , Go straight back to  0xBB7  Corresponding characters  -> 'ஷ'

String.formCodePoint()   <--- Characters and   Code points   Cross conversion -->   ' character '.codePointAt()
String.fromCharCodde()   <--- Characters and   Code points   Cross conversion -->   ' character '.charCodeAt()

2、‘ character ’.codePointAt() and ‘ character ’.charCodeAt(): Convert characters to decimal code points , If you want hexadecimal code points, you can use toString(16) Switch down
‘ character ’.codePointAt() Four byte characters can be recognized , and ‘ character ’.charCodeAt() Only two byte characters can be recognized

'𠮷'.codePointAt().toString(16) // 0x20BB7
'𠮷'.charCodeAt().toString(16) // d842

3、String.raw character : Will translate the characters that need to be translated \ Translate again

String.raw`\\ndasdasa`  //  return  \\\\ndasdasa

4、‘Unicode character ’.normallize() Method ： It is used to unify different representations of the same character , namely Unicode Normalization of

'\u01D1'.normalize() === '\u004F\u030C'.normalize()  // \u01D1  and  \u004F\u030C  Both represent the same characters 

5、includes()、startsWith()、endsWith(): Determine whether a character contains a character

 'asdfrew345'.includes('fre') // true --> 'asdfrew345'  Does it include  ’fre‘
 'asdfrew345'.includes('aaa') // false --> 'asdfrew345'  Does it include  ’aaa‘

 'asdfrew345'.startsWith('fre') // false --> 'asdfrew345'  Is the front of  ’fre‘
 'asdfrew345'.startsWith('asd') // true --> 'asdfrew345'  Is the front of  ’asd‘

 'asdfrew345'.startsWith('fre') // false --> 'asdfrew345'  Whether the tail of is  ’fre‘
 'asdfrew345'.startsWith('345') // true --> 'asdfrew345'  Whether the tail of is  ’345‘

6、‘ character ’.repeat(n): Copy the original character n Time

'a'.repeat(Infinity) // RangeError --->  Less than  0  Will report a mistake 
'a'.repeat(-2) // RangeError --->  Less than  0  Will report a mistake 
'a'.repeat(-1.4) // RangeError --->  Less than  0  Will report a mistake 

'a'.repeat(NaN) // ''
'a'.repeat(-0.6) // '' ---> -1~0 Between   Will return to empty 

'a'.repeat(3.2) // 'aaa' --->  Ignore decimals , Integer 
'a'.repeat(2) // 'aa'

7、padStart()、padEnd(): Completion of string

'ab'.padStart(5, 'xy') // 'xyxab'  In string  'ab'  Head complement  'xy', The total length of  5
'ab'.padStart(5) // ' ab'  In string  'ab'  The header of the default fill empty characters  '', The total length of  5
'abwew'.padStart(5, 'xy') // 'abwew'


'ab'.padEnd(5, 'xy') // 'abxyx'  In string  'ab'  Tail completion of  'xy', The total length of  5
'ab'.padEnd(5) // 'ab '  In string  'ab'  The default completion of the tail of empty characters  '', The total length of  5
'abwew'.padEnd(5, 'xy') // 'abwew'

8、trim()、trimStart()、trimEnd()、trimLeft()、trimRight(): Eliminate string spaces

' aa da '.trim() //  Eliminate all spaces at the beginning and end of the string  --- > 'aa da'
' aa da '.trimStart() //  Eliminate all spaces in the string header  --- > 'aa da '
' aa da '.trimLeft() //  Eliminate all spaces in the string header  --- > 'aa da '
' aa da '.trimEnd() //  Eliminate all spaces at the end of the string  --- > ' aa da'
' aa da '.trimRight() //  Eliminate all spaces at the end of the string  --- > ' aa da'

9、‘ character ’.replace() and ' character ’replaceAll(); Replace some characters in the characters

//  Replace the first character from left to right in the string  'a'  by  '-'
'aagafewrqw'.replace('a', '-') // '-agafewrqw'
//  Replace all characters in the string  'a'  by  '-' 
'aagafewrqw'.replace(/a/g, '-') // '--g-fewrqw'
//  Replace the first character from left to right in the string ( Case insensitive ) 'a'  by  '-'
'Aagafewrqw'.replace(/a/i, '-') // '-agafewrqw'



//  Replace all characters in the string  'a'  by  '-'
'aagafewrqw'.replaceAll('a', '-') // '--g-fewrqw'
//  The second argument can be a function 
'aabbcc'.replaceAll('b', () => '_') // 'aa__cc'
// $&  Represents the matching string itself , namely `b` In itself ,  So the returned result is consistent with the original string 
'abbc'.replaceAll('b', '$&')  // 'abbc'
// $`  Represents the string before the matching result ,  For the first `b`,$`  Refer to `a`,  For the second `b`,$`  Refer to `ab`
'abbc'.replaceAll('b', '$`') // 'aaabc'
// $'  Represents the string after the matching result ,  For the first `b`,$'  Refer to `bc`,  For the second `b`,$'  Refer to `c`
'abbc'.replaceAll('b', `$'`) // 'abccc'
// $1  Represents the first group match of a regular expression , Refer to `ab`,$2  Represents the second group match of regular expressions , Refer to `bc`
'abbc'.replaceAll(/(ab)(bc)/g, '$2$1') // 'bcab'
// $$  Refer to   Dollar symbol  $
'abc'.replaceAll('b', '$$') // 'a$c'


const str = 'aa123abc456aa',  regex = /(\d+)([a-z]+)(\d+)/g;
function replacer(match, p1, p2, p3, offset, string) {
    
  console.log(match) //  Matching content  ---》 123abc456
  console.log(p1) //  Group 1 ---》 123
  console.log(p2) //  Group 2 ---》 abc
  console.log(p3) //  Group 3 ---》 456
  console.log(offset) //  The location of the matching content  ---》 0
  console.log(string) //  Full string  ---》 aa123abc456aa
  return [p1, p2, p3].join(' - ');
}
str.replaceAll(regex, replacer) // aa123 - abc - 456aa

10、‘ character ’.at( Indexes )： Gets the character at the specified position

'das'.at(-1) // 's'
'das'.at(-2) // 'a'
'das'.at(-3) // 'd'
'das'.at(-4) // undefined

'das'.at(666) // undefined
'das'.at(2) // 's'
'das'.at(1) // 'a'
'das'.at(0) // 'd'

'das'.at(true) // 'a'
'das'.at(false) // 'd'
'das'.at(NaN) // 'd'
'das'.at('fafdafdafdsafa') // 'd'

That's the record , I wish you all happiness ~