Template_string.js

Template_string.js

//first, checks if it isn't implemented yet
if (!String.prototype.format) {
  String.prototype.format = function() {
    var args = arguments;
    return this.replace(/{(\d+)}/g, function(match, number) { 
      return typeof args[number] != 'undefined'
        ? args[number]
        : match
      ;
    });
  };
}
"{0} is dead, but {1} is alive! {0} {2}".format("ASP", "ASP.NET")
​
outputs
​
ASP is dead, but ASP.NET is alive! ASP {2}

To use template strings in JavaScript ES6 without a library for older browsers.