createJSONFormatter.js

/**
 * A JSON formatter that transforms the incoming
 * stream of JSON data (without proper formatting)
 * into properly formatted JSON string.
 * Usage:
 *   yourInputStream.pipe(createJSONFormatter()).pipe(yourOutputStream);
 */

const Transform = require('stream').Transform;

function createJSONFormatter() {
  const formatter = Transform();
  formatter.jsonData = '';
  
  // Process every chunk and accumulate
  formatter._transform = function (chunk, enc, cb) {
    this.jsonData += chunk.toString();
    cb();
  }
  
  // Format the JSON at the end of the stream
  formatter._flush = function (cb) {
    const json = JSON.stringify(JSON.parse(this.jsonData), null, 2);
    this.push(json);
    cb();
  }
  
  return formatter;
}

module.exports = createJSONFormatter;