# coro-wrapper
Documentation for the coro-wrapper module, version 3.1.0.
coro-wrapper is an adapter module for applying decoders/encoders/merger adapters to coro-channel readers and writers.
Understanding this and how it works can be a bit tricky. But think about it like this: You have a reader that returns an HTTP chunk back as the raw HTTP string, and you want to make that reader return a parsed version of that HTTP chunk, so you apply the decoder adapter on that reader to provide an abstraction over the lower level return, this is in fact how coro-http does it!
The rest of the adapters have a similar concept.
# Installation
lit install creationix/coro-wrapper
# Functions
# merger(read, scan)
Returns an adapter that merges multiple chunks together as a one return per call.
# Parameters
| Param | Type | Description |
|---|---|---|
| read | function | Supposedly the coro-channel’s reader you’ll be adapting, though any wrapper that returns a chunk of data each time it is called would work. |
| scan | function | A callback that takes the read chunk of data, and either returns true to flush and return the buffer, or a falsely value to keep waiting for more data to be read. |
# Returns
| Return | Type | Description |
|---|---|---|
| read | function | Reads stream chunks (possibly while yielding the current coroutine) till the whole buffer is consumed or till scan returns a truthy value, then returns the read chunks concatenated in a single string buffer. |
| updateScan | function | A function that takes a single function parameter and set scan to that input. |
# decoder(read, decode)
Returns an adapter of read, where it keeps building a buffer of the read chunks, and when enough data is supplied, it will be decoded using decode and the return of that will be the adapter result, while still allowing you to hot-swipe the decoder.
# Parameters
| Param | Type | Description |
|---|---|---|
| read | function | Supposedly the coro-channel’s reader you’ll be adapting, though any wrapper that returns a chunk of data each time it is called would work. |
| decode | function | A callback that gets called on each chunk read while taking the string buffer and its current index as inputs. If a nil is returned the adapter will keep listening for more data to build the buffer with.Otherwise, the returned value will be considered as if it were the decoder result, and the buffer will be flushed. If a second value of type number is returned that would be considered as the new buffer index to start at, meaning, any data in the buffer before the supplied index will be trimmed down. |
# Returns
| Return | Type | Description |
|---|---|---|
| read | function | Reads stream chunks (possibly while yielding the current coroutine) till enough data is supplied (determined by decode), then returns the decoded item by decode. |
| updateDecode | function | A function that takes a single function parameter and set decode to that input. |
# encoder(write, encode)
Returns an adapter of write, where it allows you to write the returns of encode into the stream while at the same time allowing you to hot-swipe the encoder.
# Parameters
| Param | Type | Description |
|---|---|---|
| write | function | Supposedly the coro-channel’s writer you’ll be adapting, though any wrapper that takes input and writes it to stream would work. |
| encode | function | A callback that takes the adapter input and returns the actual data chunk to be written. |
# Returns
| Return | Type | Description |
|---|---|---|
| … | Any | Returns everything write returns. |