'use strict'; require('../common'); const assert = require('assert'); const stream = require('stream'); const util = require('util'); function MyWritable(fn, options) { stream.Writable.call(this, options); this.fn = fn; } util.inherits(MyWritable, stream.Writable); MyWritable.prototype._write = function(chunk, encoding, callback) { this.fn(Buffer.isBuffer(chunk), typeof chunk, encoding); callback(); }; { const m = new MyWritable(function(isBuffer, type, enc) { assert(isBuffer); assert.strictEqual(type, 'object'); assert.strictEqual(enc, 'buffer'); }, { decodeStrings: true }); m.write('some-text', 'utf8'); m.end(); } { const m = new MyWritable(function(isBuffer, type, enc) { assert(!isBuffer); assert.strictEqual(type, 'string'); assert.strictEqual(enc, 'utf8'); }, { decodeStrings: false }); m.write('some-text', 'utf8'); m.end(); }