This is a nice formatter for strings in javascript

formatString.js

+String.prototype.format = function (placeholders) {
 +    var s = this;
 +    for (var propertyName in placeholders) {
 +        var re = new RegExp('{' + propertyName + '}', 'gm');
 +        s = s.replace(re, placeholders[propertyName]);
 +    }
 +    return s;
 +};
 
 console.log("Hi my name is ${name} and i'm {$age} years old".format({name: "Andrew", age: "30"}))