Stream-Based Custom Test Reporter Engine Built on node:test Lifecycle

import { Transform } from 'node:stream';
import { run } from 'node:test';
 
class TestSummaryReporter extends Transform {
  constructor() {
    super({ writableObjectMode: true });
    this.passed = 0;
    this.failed = 0;
  }
 
  _transform(event, encoding, callback) {
    if (event.type === 'test:pass') this.passed++;
    if (event.type === 'test:fail') this.failed++;
    callback();
  }
 
  _flush(callback) {
    this.push(`Test Summary -> Passed: ${this.passed}, Failed: ${this.failed}\n`);
    callback();
  }
}
 
const reporter = new TestSummaryReporter();
reporter.on('data', chunk => console.log(chunk.toString()));
run({ files: [] }).compose(reporter);