string.format function code in js_javascript skills

String. prototype.format = function(args) {
if (arguments.length>0) {
var result = this;
if (arguments.length == 1 && typeof (args) == "object" ) {
for (var key in args) {
var reg=new RegExp ("({" key "})","g");
result = result.replace(reg, args[ key]);
}
}
else {
for (var i = 0; i < arguments.length; i ) {
if(arguments[i]==undefined)
{
return "";
}
else
{
var reg=new RegExp ("({[" i "]})","g");
result = result.replace(reg, arguments[i]);
}
}
}
return result;
}
else {
return this;
}
}

//Two calling methods
var template1="I am {0}, and I am {1} this year";
var template2="I am {name}, and I am {age} this year. ";
var result1=template1.format("loogn",22);
var result2=template1.format({name:"loogn",age:22});
//Two results They are all "I am loogn, I am 22 this year"