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

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

const stream = require('stream');
const util = require('util');

function MyWritable(options) {
  stream.Writable.call(this, options);
}

util.inherits(MyWritable, stream.Writable);

MyWritable.prototype._write = function(chunk, encoding, callback) {
  assert.notStrictEqual(chunk, null);
  callback();
};

common.expectsError(
  () => {
    const m = new MyWritable({ objectMode: true });
    m.write(null, (err) => assert.ok(err));
  },
  {
    code: 'ERR_STREAM_NULL_VALUES',
    type: TypeError,
    message: '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);
  });
});

common.expectsError(
  () => {
    const m = new MyWritable();
    m.write(false, (err) => assert.ok(err));
  },
  {
    code: 'ERR_INVALID_ARG_TYPE',
    type: TypeError
  }
);

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);
  });
});