correct-highland.js

let highland = require("highland");
let Transform = require("stream").Transform;
let byline = require("byline");

class AsyncTransformStream extends Transform {
    _transform(chunk, encoding, callback) {
        setImmediate(() => {
            this.push(chunk + "\n");
            callback();
        });
    }
}

highland(byline(process.stdin, {encoding: "utf8"}))
    .map(value => value.trim())
    .pipe(new AsyncTransformStream)
    .pipe(process.stdout);

incorrect-highland.js

let highland = require("highland");
let Transform = require("stream").Transform;
let byline = require("byline");
let trimAttributes = highland().map(value => value.trim());

class AsyncTransformStream extends Transform {
    _transform(chunk, encoding, callback) {
        setImmediate(() => {
            this.push(chunk + "\n");
            callback();
        });
    }
}

byline(process.stdin, {encoding: "utf8"})
    .pipe(trimAttributes)
    .pipe(new AsyncTransformStream)
    .pipe(process.stdout);

package.json

{
  "name": "highland-experiment",
  "version": "1.0.0",
  "description": "",
  "main": "correct-highland.js",
  "dependencies": {
    "byline": "^4.2.1",
    "highland": "^2.5.1"
  },
  "devDependencies": {},
  "scripts": {
    "test": "echo \"Error: no test specified\" && exit 1"
  },
  "author": "",
  "license": "ISC"
}