如何使用节点流创建数组然后访问数据答案

【问题标题】：How to create an array with node stream and then access the data如何使用节点流创建数组然后访问数据
【发布时间】：2023-02-09 21:34:52
【问题描述】：

我需要访问一个目录，我将使用带有生成器的流，并且对于每个文件，我将推送到 myArray 数组。如何返回填充的数组，在这种情况下它返回空，即使在遍历流之后也是如此？

const { Readable, Transform, Writable } = require('node:stream')

const myArray = []

class ReadStream extends Readable {
  i = 0

  _read() {
    if (this.i >= 10) {
      this.push(null)
    } else {
      this.i++
      const str = String(this.i)
      const buf = Buffer.from(str, 'ascii')
      console.clear()
      this.push(buf)
    }
  }
}

class TransformStream extends Transform {
  _transform(chunk, encoding, callback) {
    const transformed = chunk.toString().toLowerCase()

    callback(null, Buffer.from(String(transformed)))
  }
}

class WriteStream extends Writable {
  _write(chunk, encoding, callback) {
    const write = chunk.toString()

    myArray.push(write)

    callback()
  }
}

new ReadStream().pipe(new TransformStream()).pipe(new WriteStream())

在这种情况下，我将如何返回填充的 myArray 数组？

【问题讨论】：

标签： javascript node.js arrays node-streams

【解决方案1】：

如果您必须使用写入流，请再次给我留言，尝试这个：

const { Readable, Transform, Writable } = require('node:stream')

const myArray = []

class ReadStream extends Readable {

  i = 0

  _read() {
    if (this.i >= 10) {
      this.push(null)
    } else {
      this.i++
      const str = String(this.i)
      const buf = Buffer.from(str, 'ascii')
      this.push(buf)
    }
  }
}

class TransformStream extends Transform {
  _transform(chunk, encoding, callback) {
    const transformed = chunk.toString().toLowerCase()
    
    callback(null, Buffer.from(String(transformed)))
  }
}

new ReadStream().pipe(new TransformStream())
.on("data", function (chunk) {
  const write = chunk.toString()
  myArray.push(write)
})
.on('end',function write() {
  
  // console.clear()
  console.log(myArray);
  })

编辑：使用 Writestream：

const { Readable, Transform, Writable } = require('node:stream')

const myArray = []

class ReadStream extends Readable {
  i = 0

  _read() {
    if (this.i >= 10) {
      this.push(null)
    } else {
      this.i++
      const str = String(this.i)
      const buf = Buffer.from(str, 'ascii')
      console.clear()
      this.push(buf)
    }
  }
}

class TransformStream extends Transform {
  _transform(chunk, encoding, callback) {
    const transformed = chunk.toString().toLowerCase()

    callback(null, Buffer.from(String(transformed)))
  }
}

class WriteStream extends Writable {
  _write(chunk, encoding, callback) {
    const write = chunk.toString()

    
    callback()
  }
  _final(callback){
    
    myArray.push(write)
    callback()
  }
}

new ReadStream().pipe(new TransformStream()).pipe(new WriteStream())

console.log(myArray);

【讨论】：