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.

It's not clear what kind of result you want. If it turns to CSV file, you want the keys to be the header or just list keys and values together in a line? — Carr, May 16 '20 at 08:45
Does this answer your question? [How can I convert JSON to CSV?](https://stackoverflow.com/questions/1871524/how-can-i-convert-json-to-csv) — Momin, May 16 '20 at 08:46
Does this answer your question? [How to convert JSON to CSV format and store in a variable](https://stackoverflow.com/questions/8847766/how-to-convert-json-to-csv-format-and-store-in-a-variable) — pritam, May 16 '20 at 08:46
@pritam I did try the samples in the code you mentioned but I believe its use case was a tad different. — Devarshi Goswami, May 16 '20 at 09:31

Carr · Accepted Answer · 2020-05-16T09:32:51.713

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();
});

edited May 16 '20 at 09:32

answered May 16 '20 at 09:05

Carr

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i get ReferenceError: object1 is not defined – Devarshi Goswami May 16 '20 at 09:08
oh, that is typo – Carr May 16 '20 at 09:09
Also, if I use map func instad of filter I get another error at line ` a.Attributes.forEach(element => {` – Devarshi Goswami May 16 '20 at 09:10
What kind of problem? – Carr May 16 '20 at 09:11
TypeError: Cannot read property 'forEach' of undefined.. I do get a CSV with your suggested code. Thanks! but there needs to be a delimiter after one row of data cuz I'm getting everything in the same row.How do I do that? – Devarshi Goswami May 16 '20 at 09:14
and this is how its showing, with the headers inside the cells as well ..```name email UserCreateDate UserStatus10mintest07 hru58109@zzrgg.com 2020-05-11T19:45:28.642000+05:30 CONFIRMED10mintest08 flmhiknaajfmbnenxf@awdrt.com ``` – Devarshi Goswami May 16 '20 at 09:15
@DevarshiGoswami, sorry about the filter part, it's my bad I overlook it, you just keep your code in that part, sorry! I just show the same code as you already did. – Carr May 16 '20 at 09:17
@DevarshiGoswami, I updated the answer, just append one more `\n` for a newline. – Carr May 16 '20 at 09:23

Convert JSON to CSV using javascript

1 Answers1