through2-map
This is a super thin wrapper around through2 that works like Array.prototype.map
but for streams.
For when through2 is just too verbose 😉
Note you will NOT be able to skip chunks. This is intended for modification only. If you want filter the stream content, use either through2
or through2-filter
. This transform also does not have a flush
function.
IMPORTANT: If you return null
from your function, the stream will end there.
var map = var truncate = // vs. with through2:var truncate = // Then use your map:source // Additionally accepts `wantStrings` argument to convert buffers into stringsvar stripTags = // Works like `Array.prototype.map` meaning you can specify a function that// takes up to two* arguments: fn(chunk, index)var spaceout = // vs. with through2:var spaceout =
*Differences from Array.prototype.map
:
- Cannot insert
null
elements into the stream without aborting. - No third
array
callback argument. That would require realizing the entire stream, which is generally counter-productive to stream operations. Array.prototype.map
doesn't modify the source Array, which is somewhat nonsensical when applied to streams.
API
require("through2-map")([options,] fn)
Create a stream.Transform
instance that will call fn(chunk, index)
on each stream segment.
var Tx = require("through2-map").ctor([options,] fn)
Create a reusable stream.Transform
TYPE that can be called via new Tx
or Tx()
to create an instance.
require("through2-map").obj([options,] fn)
Create a through2-map
instance that defaults to objectMode: true
.
require("through2-map").objCtor([options,] fn)
Just like ctor, but with objectMode: true
defaulting to true.
Options
- wantStrings: Automatically call chunk.toString() for the super lazy.
- all other through2 options
LICENSE
MIT