JS string encoding and Unicode encoding mutual transfer

Convert string encoding to Unicode encoding
function Chartounicode (str) {let    temp;    Let i = 0;    Let r = ';    Let len = str.length;     for (; i < Len; i++) {        temp = str.charcodeat (i). toString (+);         while (Temp.length < 4)        temp = ' 0 ' + temp;         R + = ' \\u ' + temp;    };    return r;}                

　　

Unicode encoding to string encoding
function Unicodetochar (str) {   //scheme one  return eval ("'" + str + "'");  Scenario Two  return unescape (Str.replace (/\u/g, "%u");  }

JS Gets the string length (the true number of characters)//Because the ES5 is preceded by a character "??" which consists of such four bytes. ("??". length = = 2) is processed into 2 lengths, so use the "for of" method to correctly traverse the length of the string function GetLength (str) {let    length = 0;    For (let Val of str) {        length++    }          return length  }

　　

The Codepointat method is the simplest way to test whether a character is made up of two bytes or four bytes. function Is32bit (c) {  return C.codepointat (0) > 0xFFFF;} Is32bit ("??")//Trueis32bit ("ah")//Falseis32bit ("a")//False

　　

In practice, the general design will think that Chinese characters such as ' ah ', ' oh ', ' sum ', ', ' are understood as two lengths, English characters and numbers such as ' A ', ' 1 ', ', ' are understood as a length, so this method can get them to think of the string length (note, not the true length of the string Just the designer understands the length) function getviewlength (str) {let    length = 0;    For (let C of str) {///note using for of is the length of the string to be correctly traversed, while other methods will "??" As a two-length traverse        if (c.codepointat (0) > 0x00FF) {length = length + 2}//either two-byte word such as ' ah ', or four-byte character '??‘，都‘当成‘是属于两个字符长度的范围

' else{length++}} return length}

　　

　　

JS string encoding and Unicode encoding mutual transfer