String array to object array with key-value pair inside the string

Question

I want to construct an object array with key-value pair from a string array.

the string array format:

['<ISO Date> - <Log Level> - {"user_id: "<UUID>", "details": "<message event/action description>", "err": "<Optionall, error description>"}']

the object array format:

[{"timestamp": <Epoch Unix Timestamp>, "loglevel": "<loglevel>", "transactionId: "<UUID>", "err": "<Error message>" }]

stringArray = [
   "2021-08-09T02:12:51.259Z - error - {\"user_id\":\"1234-1111\",\"details\":\"Cannot find user orders list\",\"code\": 404,\"err\":\"Not found\"}",
   "2022-08-09T02:12:51.275Z - error - {\"user_id\":\"1111-1234\",\"details\":\"Cannot find user orders list\",\"code\":404,\"err\":\"Cannot find user orders list"}"
];

objectArray = [
   {
      "timestamp":1628475171259,
      "loglevel":"error",
      "userId":"1234-1111",
      "err":"Not found"
   },
   {
      "timestamp":1660011171275,
      "loglevel":"error",
      "userId":"1111-1234",
      "err":"Cannot find user orders list"
   }
];

Answer 1

You may deconstruct each line as "timestamp" - "logLevel" - "jsonStringified"

The later can be JSON.parsed to retrieve the object

Note that maybe you should ensure that every line holds the format. Otherwise you would have errors to handle (what if no jsonStringified, what is someone else outputted some random lines, etc)

stringArray = [
   "2021-08-09T02:12:51.259Z - error - {\"transactionId\":\"9abc55b2-807b-4361-9dbe-aa88b1b2e978\",\"details\":\"Cannot find user orders list\",\"code\": 404,\"err\":\"Not found\"}",
   "2022-08-09T02:12:51.275Z - error - {\"transactionId\":\"9abc55b2-807b-4361-9dbe-aa88b1b2e978\",\"details\":\"Cannot find user orders list\",\"code\":404,\"err\":\"Cannot find user orders list\"}"
];
const tsCapture = '(.{'+"2022-08-09T02:12:51.275Z".length+'})'
const levelCapture = '(error|warning|debug)'
const stringCapture = '(.+)'
const reg = new RegExp('^'+tsCapture + ' - ' + (levelCapture) + ' - ' + stringCapture+'$')

const parsed = stringArray.map(line => {
  const [_, timestamp, logLevel, str] = line.match(reg)
  return {timestamp, logLevel, ...JSON.parse(str)}
})

console.log({ parsed })

Answer 2

In Java, you can do this by splitting using tokens

JSONArray jsonArray = new JSONArray();
        for(int i=0;i<stringArray.length; i++) {
            String string = stringArray[i];
            String[] stringSplit = string.split(" - ");
            JSONObject object = new JSONObject();
            object.put("timestamp", stringSplit[0]);
            object.put("loglevel", stringSplit[1]);
            String[] transtactionDetailSplit = stringSplit[2].split(":|,");
            object.put("transactionId", transtactionDetailSplit[1]);
            object.put("err", transtactionDetailSplit[7]);
            jsonArray.add(object);
        }
        System.out.println(jsonArray);

Kindly add null check wherever needed