'use strict'; const common = require('../common'); const stream = require('stream'); const assert = require('assert'); const transform = new stream.Transform({ transform: _transform, highWaterMark: 1 }); function _transform(chunk, encoding, cb) { assert.strictEqual(transform._writableState.needDrain, true); cb(); } assert.strictEqual(transform._writableState.needDrain, false); transform.write('asdasd', common.mustCall(() => { assert.strictEqual(transform._writableState.needDrain, false); })); assert.strictEqual(transform._writableState.needDrain, true);