how to parse data from two csv in node.js - node.js

Question

I am very new to node.js. I have one script that will parse the csv and generate the required output file. Now I want to fetch some of column data from another csv at the same time and add that value to the output file.
Script :
var csv = require('csv');
var fs = require('fs');
var progress = require('progress-stream');
var date = require('date-and-time');
var indexStat = 0;
var header = [];
var headerLine = '$lang=en\n\nINSERT_UPDATE Customer;uid;name;address;phoneno'
var delimeter = ',';
var semicolon = ';';
var inputFile = __dirname+'/project/customer.csv';
var outputFile = __dirname+'/project/customer.impex';
var inputFileName = 'customer.csv';
var outputFileName = 'customer.impex';
function generateRecord(json) {
var record = semicolon + json.uid + semicolon + json.name + semicolon + json.address;
return record;
}
var writeStream = fs.createWriteStream(outputFile);
var parser = csv.parse({
delimiter: delimeter
}, function (err, data) {
if (err) {
console.log(err);
}
});
var transformer = csv.transform(function (data) {
var line = '';
if (indexStat == 0) {
header = data;
var line = headerLine;
} else {
var line = generateRecord(generateRecordObject(data));
}
indexStat++;
writeStream.write(line + '\r\n');
});
function stringSplitter(dataRow) {
var str = dataRow.toString();
return str.split(delimeter);
}
function generateRecordObject(dataRow) {
var record = {};
dataRow.forEach(function (value, index) {
if (header[index] != '') {
record[header[index].toLowerCase()] = value;
}
});
return record;
}
var stat = fs.statSync(inputFile);
var str = progress({
length: stat.size,
time: 100
});
str.on('progress', function (progress) {
writeCompletedPercentageForRead(progress.percentage, progress.eta, progress.runtime, progress.speed);
});
function removeLineBreaks(obj) {
obj = obj.replace(/\\N/g, '');
obj = obj.replace(/&/g, '&');
return obj;
}
function writeCompletedPercentageForRead(p, e, r, s) {
process.stdout.clearLine();
process.stdout.cursorTo(0);
process.stdout.write(`${inputFileName} read in progress to write ${outputFileName} ... Completed:${parseInt(p, 10)} %, ETA:${e} seconds, Elapsed:${r} seconds, Rate:${parseInt(s/1024, 10)} KBps`);
};
fs.createReadStream(inputFile).pipe(str).pipe(parser).pipe(transformer);
customer.csv ->
uid,name,address
1234,manish,bangalore
The above script is working fine and generating customer.impex file as below
INSERT_UPDATE Customer;uid;name;address;phoneno
;1234;manish;bangalore
Now i want to populate phoneno as well but phoneno field is define in another csv file lets say 'customer_phone.csv'.
customer_phone.csv -
uid,phoneno
1234,98777767467
I want to match uid column of customer.csv with customer_phone.csv and get the phoneno from that csv. Finally i want to add phoneno in the customer.impex outfile file.
I have no idea how to parse two csv here and generate the file. Any help ?

Answer 1

var Converter = require("csvtojson").Converter;
var fs = require("fs");
var pathToMainCSV = "./customer.csv";
var pathToContactsCSV = "./contact.csv";
var customerConverter = new Converter({});
var contactConverter = new Converter({});
var contanierObj = {};
function processContacts() {
fs.createReadStream(pathToContactsCSV).pipe(contactConverter);
}
function createImpexFile() {
var headerLine = '$lang=en\n\nINSERT_UPDATE Customer;uid;name;address;phoneno;\n';
Object.keys(contanierObj).forEach(obj => {
Object.keys(contanierObj[obj]).forEach(data => {
headerLine += contanierObj[obj][data] + ';';
});
headerLine += '\n';
});
fs.writeFile("./new.impex", headerLine, function(err) {
if (err) {
return console.log(err);
}
console.log("The file was saved!");
});
}
customerConverter.on("end_parsed", function(jsonArray) {
jsonArray.forEach(v => {
contanierObj[v.uid] = v;
});
processContacts();
});
contactConverter.on("end_parsed", function(jsonArray) {
jsonArray.forEach(v => {
contanierObj[v.uid].contact = v.phoneno;
});
createImpexFile();
});
fs.createReadStream(pathToMainCSV).pipe(customerConverter);
Kindly use something like i have done above, format the string according to your needs