test/parallel/test-stream-writable-change-default-encoding.js

// Copyright Joyent, Inc. and other Node contributors.
//
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// copy of this software and associated documentation files (the
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// persons to whom the Software is furnished to do so, subject to the
// following conditions:
//
// The above copyright notice and this permission notice shall be included
// in all copies or substantial portions of the Software.
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// OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
// MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN
// NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM,
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'use strict';
require('../common');
const assert = require('assert');

const stream = require('stream');

class MyWritable extends stream.Writable {
  constructor(fn, options) {
    super(options);
    this.fn = fn;
  }

  _write(chunk, encoding, callback) {
    this.fn(Buffer.isBuffer(chunk), typeof chunk, encoding);
    callback();
  }
}

(function defaultCondingIsUtf8() {
  const m = new MyWritable(function(isBuffer, type, enc) {
    assert.strictEqual(enc, 'utf8');
  }, { decodeStrings: false });
  m.write('foo');
  m.end();
}());

(function changeDefaultEncodingToAscii() {
  const m = new MyWritable(function(isBuffer, type, enc) {
    assert.strictEqual(enc, 'ascii');
  }, { decodeStrings: false });
  m.setDefaultEncoding('ascii');
  m.write('bar');
  m.end();
}());

// Change default encoding to invalid value.
assert.throws(() => {
  const m = new MyWritable(
    (isBuffer, type, enc) => {},
    { decodeStrings: false });
  m.setDefaultEncoding({});
  m.write('bar');
  m.end();
}, {
  name: 'TypeError',
  code: 'ERR_UNKNOWN_ENCODING',
  message: 'Unknown encoding: {}'
});

(function checkVariableCaseEncoding() {
  const m = new MyWritable(function(isBuffer, type, enc) {
    assert.strictEqual(enc, 'ascii');
  }, { decodeStrings: false });
  m.setDefaultEncoding('AsCii');
  m.write('bar');
  m.end();
}());