Javascript String fromCharCode()

Introduction

The Javascript String fromCharCode() method can create a string from their UTF-16 code unit representation. 

String.fromCharCode(num1[, ...[, numN]])
  • num1,...,numN - a sequence of numbers that are UTF-16 code units.

The range is between 0 and 65535 (0xFFFF).

Numbers greater than 0xFFFF are truncated. 

let a = String.fromCharCode(65, 66, 67);   
console.log(a);/*  w  w  w  .ja  v a  2 s .com*/
a = String.fromCharCode(0x2014);       
console.log(a);
a = String.fromCharCode(0x12014);      
console.log(a);
a = String.fromCharCode(8212);         
console.log(a);

This method accepts any number of numbers and returns a string:

  • Unicode Latin small letter A is 0x61
  • Unicode Latin small letter B is 0x62
  • Unicode Latin small letter C is 0x63
  • Unicode Latin small letter D is 0x64
  • Unicode Latin small letter E is 0x65 
        
console.log(String.fromCharCode(0x61, 0x62, 0x63, 0x64, 0x65));  // "abcde"
  • 0x0061 is ascii 97
  • 0x0062 is ascii 98
  • 0x0063 is ascii 99
  • 0x0064 is ascii 100
  • 0x0065 is ascii 101 
console.log(String.fromCharCode(97, 98, 99, 100, 101));          // "abcde"

For characters in the range of U+0000 to U+FFFF, length, charAt(), charCodeAt(), and fromCharCode() all behave exactly.

The following example uses a smiley face emoji character:

The "smiling face with smiling eyes" emoji is U+1F60A. 

let message = String.fromCharCode(0x1F60A);

console.log(message.length);//from  www  .j a  v a2  s.  c  o  m
console.log(message.charAt(0));
console.log(message.charCodeAt(0)); 

console.log(String.fromCharCode(97, 98, 55357, 56842, 100, 101)); // ab?de 
console.log(message.length);
console.log(message.charAt(0));
console.log(message.charAt(1));
console.log(message.charAt(2));
console.log(message.charAt(3));
console.log(message.charAt(4));

console.log(message.charCodeAt(0)); 
console.log(message.charCodeAt(1)); 
console.log(message.charCodeAt(2)); 
console.log(message.charCodeAt(3)); 
console.log(message.charCodeAt(4));



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