Typescript generating redundant variable

Typescript generating redundant variable

Consider the following Typescript code:
module demoAppModule{
'use strict';
export module nest{
export var hello = function () {
alert('Hello!');
};
}
}
demoAppModule.nest.hello();
After transpiling we have the following javascript code:
var demoAppModule;
(function (demoAppModule) {
'use strict';
(function (nest) {
nest.hello = function () {
alert('Hello!');
};
})(demoAppModule.nest || (demoAppModule.nest = {}));
var nest = demoAppModule.nest;
})(demoAppModule || (demoAppModule = {}));
demoAppModule.nest.hello();
Why is this line generated? It hurts my eyes.
var nest = demoAppModule.nest;