Trying to change this module to work with a return statement

Question

I have a module to convert CSV to JSON using a promise however since I used a Promise instead of returning the data. The data now is to implicit and I can’t compare two CSV files. How would I be able to change the code to using a return statement.

csv to json file

const readline = require('readline');
const fs = require('fs');

function readCsv(pathToFile) {
    return new Promise((resolve, reject) => {
        // This is where your code would go (other than the "requires")
        // replace the "cats.csv" string with the "pathToFile" variable instead
        // stick this inside of your "close" handler function once the data's been assembled:
        const csvReader = readline.createInterface({
            input: fs.createReadStream(pathToFile)
        });

        let headers;
        const rows = [];
        let tempRows = [];
        csvReader
            .on('line', row => {
                if (!headers) {
                    headers = row.split(','); // header name breed age
                } else {
                    rows.push(row.split(','));
                }
            })
            .on('close', () => {
                // then iterate through all of the "rows", matching them to the "headers"
                for (var i = 0; i < rows.length; i++) {
                    var obj = {};
                    var currentline = rows[i];

                    for (var j = 0; j < headers.length; j++) {
                        obj[headers[j]] = currentline[j]; //Kitty Siamese 14
                    }

                    tempRows.push(obj);

                }

                resolve(JSON.stringify(tempRows));
            });

        // This would be in place of the "return" statement you had before
    });
}

module.exports = readCsv;

You can't. Data retrieved asynchronously cannot be returned synchronously. — CertainPerformance, Mar 25 '19 at 00:03
You're right, however I'm asking how would I remove this promise and add a return statement to get the data — Gracias Peterson Claude, Mar 25 '19 at 00:06
You're already returning a Promise - you can't change it to anything else if you want to be able to use the data elsewhere. — CertainPerformance, Mar 25 '19 at 00:08
I can't remove ```return new Promise((resolve,reject) => {... resolve(JSON.stringify(tempRows)} ``` and add a ``` return JSON.stringify(tempRows)``` ? — Gracias Peterson Claude, Mar 25 '19 at 00:12
No, if something is fetched asynchronously, you can't return that fetched data synchronously, you can only return a Promise (or use a callback function) — CertainPerformance, Mar 25 '19 at 00:12

Trying to change this module to work with a return statement

0 Answers0