I have a .log file of objects how do I convert them to a JSON object for iterating through in Javascript?

Question

Here is a sample of the .log file I need to convert. I am using Node.

    {"test": "data", "test1": 123, "foo": "feel me??"}
    {"test": "data", "test1": 123, "foo": "feel me??"}
    {"test": "data", "test1": 123, "foo": "feel me??"}

I am importing it by using this code.

let data = fs.readFileSync(log_path, 'utf8', function(err, data){
  if (err) throw err;
  let tweets = data.split('\n').map(line => JSON.parse(line));

  return tweets;

  fs.close(data, (err) => {
    console.log(err);
  })
})

As you can see it's not separated by commas so is not in JSON format. I am trying to read the file, then split it by a new line, but that doesn't seem to be working.

CertainPerformance · Accepted Answer · 2018-05-17T04:15:40.093

3

Assuming "feel me??" is meant to be a property, you could split up the lines and then map them to an array of objects:

const text = `    {"test": "data", "test1": 123, "foo": "feel me??"}
    {"test": "data", "test1": 123, "foo": "feel me??"}
    {"test": "data", "test1": 123, "foo": "feel me??"}`;
const arrOfObjs = text.split('\n')
  .map(line => JSON.parse(line));
console.log(arrOfObjs);

The other problem is that readFileSync, as its name implies, reads the file synchronously. It doesn't accept a callback like that. Change your file-reading code to:

let data = fs.readFileSync(log_path, 'utf8');
// do stuff with the `data` string

Remember that since you're not working with a stream, you don't need fs.close.

edited May 17 '18 at 04:15

answered May 17 '18 at 03:35

CertainPerformance

356,069
52
309
320

When I use fs.readFileSync on the .log file it doesn't seem to return a string I can split up. – Mark May 17 '18 at 03:42
First time you mentioned that - then you should edit your question to clarify that, and post your code – CertainPerformance May 17 '18 at 03:45
Edited. Sorry. I thought it was implied saying I was reading from a .log file in that format. – Mark May 17 '18 at 03:58
See edit - `readFileSync` runs *synchronously*, not asynchronously. It doesn't accept a callback. – CertainPerformance May 17 '18 at 04:05
Sounds like the log text you're working with doesn't match the text you posted in the question. – CertainPerformance May 17 '18 at 04:18

score 0 · Answer 2 · answered Mar 30 '20 at 01:13

Personally I used the read-last-lines package to get only a few last lines of my log file.

To make it work I had to slightly modify the code from the accepted answer, which was a great help for myself. I am going to add it here in case if someone was struggling with a similar issue.

readLastLines.read('info.log', 10)
      .then((lines) => {
        const arrOfStringObjs = lines.split('\n')
        let arrOfObjs = []
        arrOfStringObjs.forEach(strObj => {
          if (strObj !== undefined && strObj !== null && strObj !== '') {
            arrOfObjs.push(JSON.parse(strObj))
          }
        });
        console.log(arrOfObjs)

Hope it helps.

I have a .log file of objects how do I convert them to a JSON object for iterating through in Javascript?

2 Answers2