Why

```
var EventEmitter = require('events').EventEmitter;
var channel = new EventEmitter();

```

works, but

```
var EventEmitter = require('events');
var channel = new EventEmitter();

```

does not work! Actually, I have another totally different example,

```
var Currency = require('./currency)
var Cu = new Currency();

```

works, but

```
var Currency = require('./currency).Currency;
var Cu = new Currency();

```

does not work. Here is my currency.js:

```
function Currency(canadianDollar) {
    this.canadianDollar = canadianDollar;
}

module.exports = Currency;

Currency.prototype.cal = function(amount) {
    return amount * this.canadianDollar;
}

```