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

'use strict';
require('../common');
const assert = require('assert');

const stream = require('stream');

class MyWritable extends stream.Writable {
  constructor(opt) {
    super(opt);
  }

  _write(chunk, encoding, callback) {
    assert.notStrictEqual(chunk, null);
    callback();
  }
}

assert.throws(() => {
  const m = new MyWritable({ objectMode: true });
  m.write(null, (err) => assert.ok(err));
}, /^TypeError: May not write null values to stream$/);
assert.doesNotThrow(() => {
  const m = new MyWritable({ objectMode: true }).on('error', (e) => {
    assert.ok(e);
  });
  m.write(null, (err) => {
    assert.ok(err);
  });
});

assert.throws(() => {
  const m = new MyWritable();
  m.write(false, (err) => assert.ok(err));
}, /^TypeError: Invalid non-string\/buffer chunk$/);
assert.doesNotThrow(() => {
  const m = new MyWritable().on('error', (e) => {
    assert.ok(e);
  });
  m.write(false, (err) => {
    assert.ok(err);
  });
});

assert.doesNotThrow(() => {
  const m = new MyWritable({ objectMode: true });
  m.write(false, (err) => assert.ifError(err));
});
assert.doesNotThrow(() => {
  const m = new MyWritable({ objectMode: true }).on('error', (e) => {
    assert.ifError(e || new Error('should not get here'));
  });
  m.write(false, (err) => {
    assert.ifError(err);
  });
});