@basic-streams/scan

``typescript
scan(
reducer: (accumulated: A, next: N) => A,
seed: A,
stream: Stream,
): Stream
`

Creates a stream containing reducer(a, x) for each value x from the source
stream, and the latest value a produced from by the resulting stream. The
resulting stream will also have given seed as the first event.

`js
import ofMany from "@basic-streams/of-many"
import scan from "@basic-streams/scan"

const stream = ofMany([1, 2, 3], 5000)

const result = scan((acc, next) => acc + next, 0, stream)

result(x => {
console.log(x)
})

// > 0
// > 1
// > 3
// > 6

// stream: ____1____2____3
// result: 0___1____3____6
``