readable.setEncoding(encoding)

• encoding <string> 要使用的编码。
• 返回: <this>

readable.setEncoding() 方法为从 Readable 流读取的数据设置字符编码。

默认情况下，没有分配编码，流数据将作为 Buffer 对象返回。 设置编码会导致流数据作为指定编码的字符串而不是 Buffer 对象返回。 例如，调用 readable.setEncoding('utf8') 将导致输出数据被解释为 UTF-8 数据，并作为字符串传入。 调用 readable.setEncoding('hex') 将使数据以十六进制字符串格式进行编码。

Readable 流将正确地处理通过流传递的多字节字符，否则如果简单地从流中提取为 Buffer 对象，这些字符将无法正确解码。

const readable = getReadableStreamSomehow();
readable.setEncoding('utf8');
readable.on('data', (chunk) => {
  assert.equal(typeof chunk, 'string');
  console.log('Got %d characters of string data:', chunk.length);
});

• encoding <string> The encoding to use.
• Returns: <this>

The readable.setEncoding() method sets the character encoding for data read from the Readable stream.

By default, no encoding is assigned and stream data will be returned as Buffer objects. Setting an encoding causes the stream data to be returned as strings of the specified encoding rather than as Buffer objects. For instance, calling readable.setEncoding('utf8') will cause the output data to be interpreted as UTF-8 data, and passed as strings. Calling readable.setEncoding('hex') will cause the data to be encoded in hexadecimal string format.

The Readable stream will properly handle multi-byte characters delivered through the stream that would otherwise become improperly decoded if simply pulled from the stream as Buffer objects.

const readable = getReadableStreamSomehow();
readable.setEncoding('utf8');
readable.on('data', (chunk) => {
  assert.equal(typeof chunk, 'string');
  console.log('Got %d characters of string data:', chunk.length);
});