node/test/parallel/test-stream-writable-finished.js

'use strict';

const common = require('../common');
const { Writable } = require('stream');
const assert = require('assert');

// basic
{
  // Find it on Writable.prototype
  assert(Object.hasOwn(Writable.prototype, 'writableFinished'));
}

// event
{
  const writable = new Writable();

  writable._write = (chunk, encoding, cb) => {
    // The state finished should start in false.
    assert.strictEqual(writable.writableFinished, false);
    cb();
  };

  writable.on('finish', common.mustCall(() => {
    assert.strictEqual(writable.writableFinished, true);
  }));

  writable.end('testing finished state', common.mustCall(() => {
    assert.strictEqual(writable.writableFinished, true);
  }));
}

{
  // Emit finish asynchronously.

  const w = new Writable({
    write(chunk, encoding, cb) {
      cb();
    }
  });

  w.end();
  w.on('finish', common.mustCall());
}

{
  // Emit prefinish synchronously.

  const w = new Writable({
    write(chunk, encoding, cb) {
      cb();
    }
  });

  let sync = true;
  w.on('prefinish', common.mustCall(() => {
    assert.strictEqual(sync, true);
  }));
  w.end();
  sync = false;
}

{
  // Emit prefinish synchronously w/ final.

  const w = new Writable({
    write(chunk, encoding, cb) {
      cb();
    },
    final(cb) {
      cb();
    }
  });

  let sync = true;
  w.on('prefinish', common.mustCall(() => {
    assert.strictEqual(sync, true);
  }));
  w.end();
  sync = false;
}


{
  // Call _final synchronously.

  let sync = true;
  const w = new Writable({
    write(chunk, encoding, cb) {
      cb();
    },
    final: common.mustCall((cb) => {
      assert.strictEqual(sync, true);
      cb();
    })
  });

  w.end();
  sync = false;
}