rafa/docs/Stream-scan.md

Rafa.js is a Javascript framework for building concurrent applications.

Scan all values and emit a new value that is the product of calling a function
that evaluates the previous and current values. This method is like `fold`
except that it produces a new value for every upstream value.

<aside>
```js
// scan(seed: A, scanner: (A,B) => A): Stream
var stream = Rafa.stream();
var values = [];

stream.scan(0, (a,b) => a + b).each(v => values.push(v));

stream.enumerate(Rafa.Enumerator.array([1,2,3,4]);

// values: [1,3,6,10];
```
</aside>