How to Parse multiple JSON files to a Same Javascript object?

Question

There is a folder with multiple JSON files that are in the same JSON format. Each file contains the following information: first name, last name, birthday, address, and phone number. Your task is to read all files and parse the data into the same person object. The task is to list all data in any output format you choose, which can be a console as well.

This is my code in NodeJs

import {readdir, readFile} from "fs";
const dir = "./src/json";
const dirAccess = readdir(`${dir}`, (err, files) => {
  files.forEach((file) => {
    const read = readFile(`${dir}/${file}`, "utf8", (err, data) => {
      let p = JSON.parse(data);
      console.log(p);
    });
  });
});

I have my data on 'p', now my question is How can I put all the Parsed JSON data to the Same Person Object?

This is easy! Make jsonData and array; and then do array.push(p); Ill update my answer. The problem is that without the context of your JSON data added in the answer your question could be taken as wanting a single JSON object with all the data. But what you want is a JSON array with all the objects of all the files. — Obsidianlab, Apr 12 '22 at 08:51

Obsidianlab · Answer 1 · 2022-04-11T20:16:24.920

0

Create a JSON object outside the forEach function and concatenate all the JSON into that one object.

let jsonconcat = {};   
//then in the loop you do
jsonconcat = {...jsonconcat, p}

Then you can save that as a file or whatever you want to do with the JSON object.

So it should look like:

import {readdir, readFile} from "fs";
const dir = "./src/json";
let jsonconcat = {};   

const dirAccess = readdir(`${dir}`, (err, files) => {
  files.forEach((file) => {
    const read = readFile(`${dir}/${file}`, "utf8", (err, data) => {
      let p = JSON.parse(data);
      jsonconcat = {...jsonconcat, p}
      console.log(p);
    });
  });
});

edited Apr 11 '22 at 20:16

answered Apr 11 '22 at 16:43

Obsidianlab

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2

He'll also need to use `readFileSync()` or more complex callback functions. – Barmar Apr 11 '22 at 16:45
done the same, bur outside the loop the jsonconcat obj is empty – Adnan Sparrow Apr 11 '22 at 20:12
I edited my answer. Does it look like that but still not work? – Obsidianlab Apr 11 '22 at 20:16
do you get any value in jsonconcat ? outside the loop? – Adnan Sparrow Apr 11 '22 at 20:26
I don't have your JSON to test with. I would try if I did. If your console is logging something for p. It has to go into jsonconcat aswell. – Obsidianlab Apr 11 '22 at 20:28
I get empty jsonconcat obj – Adnan Sparrow Apr 11 '22 at 20:32

Obsidianlab · Answer 2 · 2022-04-12T08:53:14.680

0

Found the answer here:

JavaScript function return is empty after file read

How to make fs.readFile async await?

readdir and readFile are async so you need to let the code wait for the process to be done.

import fs, { readdir, readFile } from 'fs';
import path from 'path';
const dir = './src/json';
let jsonData = [];

async function readingDirectory(directory) {
  const fileNames = await fs.promises.readdir(directory);
  for (let file of fileNames) {
    const absolutePath = path.join(directory, file);

    const data = await fs.promises.readFile(absolutePath);
    let p = JSON.parse(data);
    console.log(absolutePath, p);
    jsonData.push(p);
  }
}

readingDirectory(dir)
  .then(() => {
    console.log(jsonData);
  })
  .catch((err) => {
    console.log(err);
  });

edited Apr 12 '22 at 08:53

answered Apr 11 '22 at 21:10

Obsidianlab

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1
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24

The way you are populating jsonData Obj doesn't work like that, it only shows the last entry – Adnan Sparrow Apr 11 '22 at 21:27
though you assigned it as empty string – Adnan Sparrow Apr 11 '22 at 21:29
For me its working but my JSON files have one object. Whats the structure if your files? – Obsidianlab Apr 11 '22 at 21:30
I assign the variable emtpy in the top but concat it with spread operators in the async function, check my answer. In the terminal you can see the two files, the contents and the final result. – Obsidianlab Apr 11 '22 at 21:33
yes, I see but for me, it's not working (as I am using typescript) I can't just spread objs in an empty string. my JSON file structure is the same with one object each. – Adnan Sparrow Apr 11 '22 at 21:43
Easy, Make let jsonData = {}; Ill edit my answer so you'll see. – Obsidianlab Apr 11 '22 at 21:44
1

check my question above I have edited it with pictures – Adnan Sparrow Apr 11 '22 at 21:55
Check my answer, I edited it again. This should work for your needs. Also check the comment i put under your original post. – Obsidianlab Apr 12 '22 at 08:58
i found one solution, actually forEach Loop does not wait for async/await, instead i used for/of the loop. now it works fine – Adnan Sparrow Apr 12 '22 at 16:09

How to Parse multiple JSON files to a Same Javascript object?

2 Answers2