js-libp2p/examples/chat/src/stream.js

/* eslint-disable no-console */

import { pipe } from 'it-pipe'
import * as lp from 'it-length-prefixed'
import map from 'it-map'
import { fromString as uint8ArrayFromString } from 'uint8arrays/from-string'
import { toString as uint8ArrayToString } from 'uint8arrays/to-string'

export function stdinToStream(stream) {
  // Read utf-8 from stdin
  process.stdin.setEncoding('utf8')
  pipe(
    // Read from stdin (the source)
    process.stdin,
    // Turn strings into buffers
    (source) => map(source, (string) => uint8ArrayFromString(string)),
    // Encode with length prefix (so receiving side knows how much data is coming)
    lp.encode(),
    // Write to the stream (the sink)
    stream.sink
  )
}

export function streamToConsole(stream) {
  pipe(
    // Read from the stream (the source)
    stream.source,
    // Decode length-prefixed data
    lp.decode(),
    // Turn buffers into strings
    (source) => map(source, (buf) => uint8ArrayToString(buf.subarray())),
    // Sink function
    async function (source) {
      // For each chunk of data
      for await (const msg of source) {
        // Output the data as a utf8 string
        console.log('> ' + msg.toString().replace('\n', ''))
      }
    }
  )
}