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# purescript-csv-stream # purescript-node-stream-pipes
Type-safe bindings for the streaming API of `csv-parse` and `csv-stringify`. Interact with node streams in object mode using [`Pipes`]!
## Example
```purescript
import Prelude
import Effect.Aff (launchAff_)
import Effect (Effect)
import Effect.Class (liftEffect)
import Effect.Console (log)
import Pipes.Prelude ((>->))
import Pipes.Prelude as Pipes
import Pipes.Core as Pipes.Core
import Pipes.Node.FS.Stream as FS
import Pipes.Node.Zlib as Zlib
import Pipes.CSV.Parse as CSV.Parse
-- == my-zipped-data.csv ==
-- id,foo,is_deleted
-- 1,hello,f
-- 2,goodbye,t
-- Logs:
-- {id: 1, foo: "hello", is_deleted: false}
-- {id: 2, foo: "goodbye", is_deleted: true}
main :: Effect Unit
main =
Pipes.Core.runEffect
$ FS.createReadStream "my-zipped-data.csv.gz"
>-> Zlib.gunzip
>-> CSV.Parse.parse @{id :: Int, foo :: String, is_deleted :: Boolean}
>-> Pipes.mapM (liftEffect <<< log)
```
## Installing ## Installing
```bash ```bash
spago install csv-stream spago install node-stream-pipes
{bun|yarn|npm|pnpm} install csv-parse csv-stringify
``` ```
## Examples [`Pipes`]: https://pursuit.purescript.org/packages/purescript-pipes/8.0.0
### Stream
```purescript
module Main where
import Prelude
import Effect (Effect)
import Effect.Class (liftEffect)
import Effect.Aff (launchAff_)
import Node.Stream (pipe)
import Node.Stream as Stream
import Node.Stream.CSV.Stringify as CSV.Stringify
import Node.Stream.CSV.Parse as CSV.Parse
type MyCSVType1 = {a :: Int, b :: Int, bar :: String, baz :: Boolean}
type MyCSVType2 = {ab :: Int, bar :: String, baz :: Boolean}
atob :: MyCSVType1 -> MyCSVType2
atob {a, b, bar, baz} = {ab: a + b, bar, baz}
myCSV :: String
myCSV = "a,b,bar,baz\n1,2,\"hello, world!\",true\n3,3,,f"
main :: Effect Unit
main = launchAff_ do
parser <- liftEffect $ CSV.Parse.make {}
stringifier <- liftEffect $ CSV.Stringify.make {}
input <- liftEffect $ Stream.readableFromString myCSV
liftEffect $ Stream.pipe input parser
records <- CSV.Parse.readAll parser
liftEffect $ for_ records \r -> CSV.Stringify.write $ atob r
liftEffect $ Stream.end stringifier
-- "ab,bar,baz\n3,\"hello, world!\",true\n6,,false"
csvString <- CSV.Stringify.readAll stringifier
pure unit
```
### Synchronous
```purescript
module Main where
import Prelude
import Effect (Effect)
import Effect.Class (liftEffect)
import Effect.Aff (launchAff_)
import Node.Stream (pipe)
import Node.Stream as Stream
import Node.Stream.CSV.Stringify as CSV.Stringify
import Node.Stream.CSV.Parse as CSV.Parse
type MyCSVType1 = {a :: Int, b :: Int, bar :: String, baz :: Boolean}
type MyCSVType2 = {ab :: Int, bar :: String, baz :: Boolean}
atob :: MyCSVType1 -> MyCSVType2
atob {a, b, bar, baz} = {ab: a + b, bar, baz}
myCSV :: String
myCSV = "a,b,bar,baz\n1,2,\"hello, world!\",true\n3,3,,f"
main :: Effect Unit
main = launchAff_ do
records :: Array MyCSVType1 <- CSV.Parse.parse myCSV
-- "ab,bar,baz\n3,\"hello, world!\",true\n6,,false"
csvString <- CSV.Stringify.stringify (atob <$> records)
pure unit
```