json data kompress

//does not reduce size?
var
base64="ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/",

trans64="abcdefghijklmnopqrstuvwxyz()[]{}:;,\"'\\!?*><&$ _-@=#\n0123456789+/"

;



var shrink_64=function(d,s){
//s = shrink (2 bit downsize)
var a,b,m,o="",L=d.length,i=0,r,c,w,z;

if(s){a=trans64;b=base64; m=d; }else{b=trans64;a=base64; m=btoa(d); }

while(i<L){
z=0;

c=m[i];
r=a.indexOf(c);


if(r<0){
 w=m.substr(0,i)+( "\\u"+(65536|c.charCodeAt(0)).toString(16).substr(1) )+m.substr(i+1); L=w.length; m=w; }else{ o+=b[r];
i++; }
}

if(s) o=atob(o);

return o;

};