Function branchAndMerge

This operator should make it easy to perform multiple calculations on the same input operator, and returning a tuple containing the multiple outputs. This can be useful for example if you need to add a timestamp, get the running average, the running max, and the running total of the same data, and you only want to iterate over the data once.

┌──────────────┐
│input iterator│
└──────┬───────┘
       │
       ├─────────────┐─────────────┐─────────────┐
       │             │             │             │
  ┌────▼────┐   ┌────▼────┐                 ┌────▼────┐
  │ transIt │   │ transIt │                 │ transIt │
  │    1    │   │    2    │       ...       │    n    │
  └────┬────┘   └────┬────┘                 └────┬────┘
       │             │             |             │
       │             │             |             │
       ├─────────────┘─────────────┘─────────────┘
       │
 <COMBINE INTO TUPLES of size n>
       │
┌──────▼────────┐
│output iterator│
└───────────────┘

All arguments are the transIterators that need to be run (use compose(for more complex operations)).

Example

await pipe(
       itr8FromArray([ 1, 2, 3, 4 ])
       branchAndMerge(
         identity(), // keep the original values as the first element of the tuple
         runningAverage(),
         runningTotal(),
       ),
       map(([value, avg, total]) => ({ value, avg, total })),
       itr8ToArray,
     )
// => [
//   { value: 1, avg: 1,   total:  1 },
//   { value: 2, avg: 1.5, total:  3 },
//   { value: 3, avg: 2,   total:  6 },
//   { value: 4, avg: 2.5, total: 10 },
// ]

Returns