Extension String:Format

If used c# you will found the function String.Format is a very powerfull string replacement method.

But in js,there just offer a replace method,and only can replace the first string fit the pattern.

Ofcourse,you can use regular expressions to achive you goal.

But it will makes your code ugly and hard to read.

So I extension String to make this point.

As usual, here is the core code.

String.prototype.Format = function() {
var returnValue = this;
for(vari = 0; i < arguments.length; i++) {
var arg = arguments[i];
var key = "";
var value = "";
//if string then find {i} to replace
if(typeof arg == "string") {
key = i;
value = arg;
} elseif(arg instanceofArray) {
//if array then trans param to params then recall
returnValue = returnValue.Format.apply(returnValue, arg);
continue;
} else{
//if object then use as keyvaluepair object
key = arg.key;
value = arg.value;
}
//setting translation symbol
var keySymple = [
{ reg: /\\/ig, value: "\\\\"},
{ reg: /\{/ig, value: "\\{"},
{ reg: /\}/ig, value: "\\}"},
{ reg: /\)/ig, value: "\\)"},
{ reg: /\(/ig, value: "\\("},
]
//translate translation symbol
for(var j = 0; j < keySymple.length; j++) {
varsympleReplace = keySymple[j];
key = key.toString().replace(sympleReplace.reg, sympleReplace.value);
}
var reg = newRegExp("\\{"+ key + "\\}", "ig");
returnValue = returnValue.replace(reg, value);
}
return returnValue;
}

Then the calling code

var demoStr="this is a {0} {1}"
demoStr.Format("hot","day")//return "this is a hot day"
demoStr.Format(["hot","day"])//return "this is a hot day"
var demoStr="my name is {Name},age {Age}"
demoStr.Format({key:"Name",value:"Happy"},{key:"Age",value:"20"})
//return "my name is Happy,age 20"
demoStr.Format([{key:"Name",value:"Happy"},{key:"Age",value:"20"}])
//return "my name is Happy,age 20"

param support params and array structure

and support string and keyvaluepair data