labeled-stream-splicer
v2.0.2
Published
stream splicer with labels
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labeled-stream-splicer
stream splicer with labels
example
Here's an example that exposes a label for deps
and pack
:
var splicer = require('labeled-stream-splicer');
var through = require('through2');
var deps = require('module-deps');
var pack = require('browser-pack');
var lstream = require('lstream');
var pipeline = splicer.obj([
'deps', [ deps() ],
'pack', [ pack({ raw: true }) ]
]);
pipeline.get('deps').unshift(lstream());
pipeline.get('deps').push(through.obj(function (row, enc, next) {
row.source = row.source.toUpperCase();
this.push(row);
next();
}));
process.stdin.pipe(pipeline).pipe(process.stdout);
Here the deps
sub-pipeline is augmented with a post-transformation that
uppercases its source input.
methods
var splicer = require('labeled-stream-splicer')
The API is the same as
stream-splicer,
except that pipeline.get()
, pipeline.splice()
, and pipeline.indexOf()
can
accept string labels in addition to numeric indexes.
var pipeline = splicer(streams, opts)
Create a pipeline
duplex stream given an array of streams
. Each stream
will be piped to the next. Writes to pipeline
get written to the first stream
and data for reads from pipeline
come from the last stream.
To signify a label, a stream may have a .label
property or a string may be
placed in the streams
array.
For example, for streams [ a, 'foo', b, c, 'bar', d ]
, this pipeline is
constructed internally:
a.pipe(b).pipe(c).pipe(d)
with a label 'foo
' that points to b
and a label 'bar'
that points to d
.
If a
or c
has a .label
property, that label would be used for addressing.
Input will get written into a
. Output will be read from d
.
If any of the elements in streams
are arrays, they will be converted into
nested labeled pipelines. This is useful if you want to expose a hookable
pipeline with grouped insertion points.
var pipeline = splicer.obj(streams, opts)
Create a pipeline
with opts.objectMode
set to true for convenience.
var removed = pipeline.splice(index, howMany, stream, ...)
Splice the pipeline starting at index
, removing howMany
streams and
replacing them with each additional stream
argument provided.
The streams that were removed from the splice and returned.
index
can be an integer index or a label.
pipeline.push(stream, ...)
Push one or more streams to the end of the pipeline.
The stream arguments may have a label
property that will be used for string
lookups.
var stream = pipeline.pop()
Pop a stream from the end of the pipeline.
pipeline.unshift(stream, ...)
Unshift one or more streams to the begining of the pipeline.
The stream arguments may have a label
property that will be used for string
lookups.
var stream = pipeline.shift()
Shift a stream from the begining of the pipeline.
var stream = pipeline.get(index)
Return the stream at index index
.
index
can be an integer or a string label.
install
With npm do:
npm install labeled-stream-splicer
license
MIT