Extract json from plain text

extract-json.js

/**
 * Example
 * Input: 'INFO Records: {"user": {"name": "luke", "type": "jedi"}}{"name": "leia"}, Record count: 2'
 * Output: [
              "INFO Records: ",
              "{\n  \"user\": {\n    \"name\": \"luke\",\n    \"type\": \"jedi\"\n  }\n}",
              "{\n  \"name\": \"leia\"\n}",
              ", Record count: 2"
            ]
 */
function extractJson(message) {
  const lines = [];
  let offset = 0;
  let last = 0;

  while (true) {
    let startIndex = message.indexOf('{', offset);
    if (startIndex < 0) {
      if (last < message.length) {
        lines.push(message.substring(last));
      }
      break;
    }
    let endIndex = startIndex;
    while (endIndex >= 0) {
      endIndex = message.indexOf('}', endIndex + 1);
      if (endIndex < 0) {
        break;
      }
      try {
        const fragment = message.substring(startIndex, endIndex + 1);
        const json = JSON.parse(fragment);
        if (last !== startIndex) {
          lines.push(message.substring(last, startIndex));
        }
        lines.push(JSON.stringify(json, null, 2));
        offset = last = endIndex + 1;
        break;
      } catch (err) {
      }
    }
    if (endIndex < 0) {
      offset++;
    }
  }
  return lines;
}