Encapsulate streams for use in object-oriented programming.
npm install stream-workflowtransform.js
const StreamFlow = require("stream-workflow");
const { Transform, pipeline } = require("stream");
const JSONStream = require("JSONStream");
const fs = require("fs");
fs.createReadStream(data.json)
.pipe(JSONStream.parse("*"))
.pipe(new Transform({
objectMode: true,
transform(chunk, enc, cb) {
cb(null, chunk);
}
}));
`
by stream-workflow
!StreamWorkflow
`stream-worflow.js
class CustomStream extends StreamFlow { {
constructor({
objectMode: true,
init(stream) { // init function must return the last stream of the pipeline.
return pipeline(
stream, // pathtrought stream
JSONStream.parse(), // Transform 1 in diagram
new Transform({ // Transform 2 in diagram
objectMode: true,
transform(chunk, enc, cb) {
cb(null, chunk);
}
}),
error => error && this.emit("error", error)
)
}
})
}
fs.createReadStream(data.json)
.pipe(new CustomStream());
`
Test
To run our tests, clone the stream-workflow repo and install the dependencies.
`bash
$ git clone https://github.com/BenoitClaveau/stream-workflow --depth 1
$ cd stream-workflow
$ npm install
$ cd tests
$ node.exe "../node_modules/mocha/bin/mocha" .
``