Convert JSON to CSV using Papaparse

Question

I have a Node JS and Typescript project in which I currently receive a JSON from an API and convert it into CSV format with a limit of lines, using the json-2-csv module. I have read that the papaparse module is quite fast for these things and I would like to know how it works but I cannot use it to convert a JSON from an api.

This is the call I make with json-2-csv:

await this.csvConverter.jsonToCsv(converterUtils, nameFile, this.dir);

This is the class that handles the conversion:

export class csvConverter {

    public async jsonToCsv (csv: any, nameFile: string, dir: string):Promise <number> {

        const max: number = new constUtils().maxRecords;
        const headers = csv.split('\n').slice(0, 1);
        const records = csv.split('\n').slice(0,);
        
        for (let i = 1; i < records.length; i = i + max) {
            let dataOut = headers.concat(records.slice(i, i + max)).join('\n');
            let id = Math.floor(i / max) + 1;
            fs.writeFileSync(`${dir}/${nameFile}.${id}.csv`, dataOut);
        }
        return Promise.resolve(csv);

    };
}

My problem is that I can't do the same with papaparse, I've looked at the documentation but I can convert JSON from local files but I can't get it from an API.

(1) Use your favorite fetch library to get JSON from the API (2) Parse the JSON into an object (`JSON.parse()`) (3) Call `Papa.unparse(yourData)`? — AKX, Jun 14 '21 at 07:58
(ps.: there's no reason to make a class for a single function, and similarly `new constUtils().maxRecords` should probably just be a `consts.maxRecords`.) — AKX, Jun 14 '21 at 07:59
@AKX Yes, I can have it in the same function. From the conversion I understand how the whole process works, my problem is that I cannot use Papaparse in this case, to convert a JSON from an api into a CSV. The ``converterUtils`` variable is the one that contains the data. — sirtz, Jun 14 '21 at 08:03
_Why_ cannot you? What have you tried? As my first comment says: get the data, parse it from JSON, pass it to Papa. — AKX, Jun 14 '21 at 08:04
@AKX These are the variables I use to make the call: ``let api = req.query.api;`` / ``let url = this.constUt.conf.API_MOCS [`$ {api}`] .url`` / ``let json = await axios.get (url);`` / ``Papa.unparse (json);``. In this case Stand Up does nothing. — sirtz, Jun 14 '21 at 08:26

score 2 · Accepted Answer · answered Jun 14 '21 at 08:29

Via comments:

These are the variables I use to make the call:
let api = req.query.api;
let url = this.constUt.conf.API_MOCS [`${api}`].url;
let json = await axios.get (url);
Papa.unparse (json);
In this case Stand Up does nothing.

axios.get returns a response object; the JSON data is available as data. You can't just pass the full response object to Papa and expect sane results.

const url = this.constUt.conf.API_MOCS[String(req.query.api)].url;
const resp = await axios.get(url);
const data = Papa.unparse(resp.data);
console.log(data);

Convert JSON to CSV using Papaparse

1 Answers1