A simple node tcp server/client with a message buffer stack to handle incoming data

simple_server_buffer.js

const net = require('net')

// Message buffer class to handle incoming data
class MessageBuffer {
  constructor(delimiter) {
    this.delimiter = delimiter;
    this.buffer = "";
  }

  isFinished() {
    if (
      this.buffer.length === 0
      || this.buffer.indexOf(this.delimiter) === -1
    ) {
      return true;
    }
    return false;
  }

  push(data) {
    this.buffer += data;
  }

  getMessage() {
    const delimiterIndex = this.buffer.indexOf(this.delimiter);
    if (delimiterIndex !== -1) {
      const message = this.buffer.slice(0, delimiterIndex);
      this.buffer = this.buffer.replace(message + this.delimiter, "");
      return message;
    }
    return null;
  }

  handleData() {
    /**
     * Try to accumulate the buffer with messages
     *
     * If the server isnt sending delimiters for some reason
     * then nothing will ever come back for these requests
     */
    const message = this.getMessage();
    return message;
  }
}

const server = new net.Server()
server.listen({host: '127.0.0.1', port: 9999})
server.on('connection', (client) => {
    client.write('{"name": "isaac",')
    setTimeout(() => {
        client.write('"age": "28"}\n{"name": "steve",') // simulate tcp fragmentation
    }, 100)
})

const client = new net.Socket()
client.connect(9999, '127.0.0.1')

let received = new MessageBuffer('\n')
client.on('data', (data) => {
    received.push(data)
    while(!received.isFinished()){
        const message = received.handleData()
        console.log(JSON.parse(message))
    }
})

client.on('close', () => {
  console.log('connection closed')
})