setEncoding（'utf8'）;

塞巴斯蒂安做得好。

我有“缓冲区问题”的几行测试代码，并添加编码信息，它解决了它，见下文。

说明问题

软件

// process.stdin.setEncoding('utf8');
process.stdin.on('data', (data) => {
    console.log(typeof(data), data);
});

输入

hello world

输出

object <Buffer 68 65 6c 6c 6f 20 77 6f 72 6c 64 0d 0a>

演示解决方案

软件

process.stdin.setEncoding('utf8'); // <- Activate!
process.stdin.on('data', (data) => {
    console.log(typeof(data), data);
});

输入

hello world

输出

string hello world

像减流器这样的东西怎么样?

下面是一个使用ES6类的例子如何使用一个。

var stream = require('stream')

class StreamReducer extends stream.Writable {
  constructor(chunkReducer, initialvalue, cb) {
    super();
    this.reducer = chunkReducer;
    this.accumulator = initialvalue;
    this.cb = cb;
  }
  _write(chunk, enc, next) {
    this.accumulator = this.reducer(this.accumulator, chunk);
    next();
  }
  end() {
    this.cb(null, this.accumulator)
  }
}

// just a test stream
class EmitterStream extends stream.Readable {
  constructor(chunks) {
    super();
    this.chunks = chunks;
  }
  _read() {
    this.chunks.forEach(function (chunk) { 
        this.push(chunk);
    }.bind(this));
    this.push(null);
  }
}

// just transform the strings into buffer as we would get from fs stream or http request stream
(new EmitterStream(
  ["hello ", "world !"]
  .map(function(str) {
     return Buffer.from(str, 'utf8');
  })
)).pipe(new StreamReducer(
  function (acc, v) {
    acc.push(v);
    return acc;
  },
  [],
  function(err, chunks) {
    console.log(Buffer.concat(chunks).toString('utf8'));
  })
);

这对我来说是有效的，并且基于Node v6.7.0文档:

let output = '';
stream.on('readable', function() {
    let read = stream.read();
    if (read !== null) {
        // New stream data is available
        output += read.toString();
    } else {
        // Stream is now finished when read is null.
        // You can callback here e.g.:
        callback(null, output);
    }
});

stream.on('error', function(err) {
  callback(err, null);
})

使用非常流行的stream-buffers包，你可能已经在你的项目依赖项中有了这个包，这是非常简单的:

// imports
const { WritableStreamBuffer } = require('stream-buffers');
const { promisify } = require('util');
const { createReadStream } = require('fs');
const pipeline = promisify(require('stream').pipeline);

// sample stream
let stream = createReadStream('/etc/hosts');

// pipeline the stream into a buffer, and print the contents when done
let buf = new WritableStreamBuffer();
pipeline(stream, buf).then(() => console.log(buf.getContents().toString()));

所有列出的答案似乎都以流动模式打开可读流，这不是NodeJS的默认模式，并且可能有局限性，因为它缺乏NodeJS在暂停可读流模式中提供的反压力支持。 这里是一个使用Just Buffers、本机流和本机流转换并支持对象模式的实现

import {Transform} from 'stream';

let buffer =null;    

function objectifyStream() {
    return new Transform({
        objectMode: true,
        transform: function(chunk, encoding, next) {

            if (!buffer) {
                buffer = Buffer.from([...chunk]);
            } else {
                buffer = Buffer.from([...buffer, ...chunk]);
            }
            next(null, buffer);
        }
    });
}

process.stdin.pipe(objectifyStream()).process.stdout

最简洁的解决方案可能是使用“string-stream”包，它将流转换为带有承诺的字符串。

const streamString = require('stream-string')

streamString(myStream).then(string_variable => {
    // myStream was converted to a string, and that string is stored in string_variable
    console.log(string_variable)

}).catch(err => {
     // myStream emitted an error event (err), so the promise from stream-string was rejected
    throw err
})