JS字符串转Byte[]

js里面的string转byte[]，这里是微信小程序代码

    stringToBytes : function ( str ) {  

        var ch, st, re = []; 
        for (var i = 0; i < str.length; i++ ) { 
            ch = str.charCodeAt(i);  // get char  
            st = [];                 // set up "stack"  

           do {  
                st.push( ch & 0xFF );  // push byte to stack  
                ch = ch >> 8;          // shift value down by 1 byte  
            }    

            while ( ch );  
            // add stack contents to result  
            // done because chars have "wrong" endianness  
            re = re.concat( st.reverse() ); 
        }  
        // return an array of bytes  
        return re;  
    } 

var str   = "000000"
var bytes = []
    bytes = stringTobytes(str)

console.log(bytes)
//[48,48,48,48,48,48]