Convert JSON to CSV using javascript

Question

I'm a total JS noob. I have read a JSON and filtered out specific items from it and saved it to a variable named mapped. How do I export this JSON to a properly formatted CSV file?

let json = require('./users.json')
let filtered = json.Users.filter((a)=>{
    return new Date(a.UserCreateDate) > new Date('2020-05-11T00:00:00.000000+05:30')
})
let mapped=filtered.map((a)=>{
    let email
    a.Attributes.forEach(element => {
        if(element.Name=='email'){
            email = element.Value
        }
    });
    return {
        name: a.Username,
        email: email,
        UserCreateDate: a.UserCreateDate,
        UserStatus: a.UserStatus
    }
})
console.log(JSON.stringify(mapped, null, 4), mapped.length)

Although there are quite a few answers to this topic, I haven't been able to successfully implement any of those.

Answer 1

I assume you wanna use the keys as the header in CSV file. What you need is to open a write stream, the format of the CSV file is pure strings with commas separating the values.

// ...
let mapped=filtered.map((a)=>{
  //...
})

// ...

const fs = require('fs');
let writeStream = fs.createWriteStream('./output.csv');
writeStream.on('open', () => {
  // get the header
  const header = Object.keys(mapped[0]).toString().concat('\n');

  writeStream.write(header);

  mapped.forEach((obj) => {
    const values = Object.values(obj).toString().concat('\n');
    writeStream.write(values);
  });
  writeStream.end();
});