currentInput.coffee

"use strict"
extend= (inp...)->
  output= {}
  for val1 in inp
    for key2,val2 of val1
      output[key2] = val2
  output

currentOutput.js

(function() {
  var extend;
  var __slice = Array.prototype.slice, __hasProp = Object.prototype.hasOwnProperty;
  "use strict";
  extend = function() {
    var _a, _b, _c, _d, inp, key2, output, val1, val2;
    inp = __slice.call(arguments, 0);
    output = {};
    _b = inp;
    for (_a = 0, _c = _b.length; _a < _c; _a++) {
      val1 = _b[_a];
      _d = val1;
      for (key2 in _d) {
        if (!__hasProp.call(_d, key2)) continue;
        val2 = _d[key2];
        output[key2] = val2;
      }
    }
    return output;
  };
})();

recommendedOutput.js

(function(__slice,__hasprop,extend) {
  "use strict";
  extend = function() {
    var _a, _b, _c, _d, inp, key2, output, val1, val2;
    inp = __slice.call(arguments, 0);
    output = {};
    _b = inp;
    for (_a = 0, _c = _b.length; _a < _c; _a++) {
      val1 = _b[_a];
      _d = val1;
      for (key2 in _d) {
        if (!__hasProp.call(_d, key2)) continue;
        val2 = _d[key2];
        output[key2] = val2;
      }
    }
    return output;
  };
})(Array.prototype.slice,Object.prototype.hasOwnProperty);