JavaScript / WebDev

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String format (JavaScript) 

String.prototype.format = function() {
    var a = arguments;
    return this.replace(/\{\d+\}/g, function(c){
        return a[c.match(/\d+/)];
    });
}
 
// usage:
var str = 'Hello, {0}! You are {1}!';
str.format('friend', 'awesome');
// Hello, friend! You are awesome!

P.S.: Вот как-то так :D