The following Node.js function requires:
- an object named
shopcontaining a regular expression - an array of filenames
This function reads each csv file listed in the array, tests a cell in the first row with the provided regular expression, and returns a new array of matching filenames.
function matchReport(shop, arr) {
return promise = new Promise(resolve => {
var newArray = [];
for(var j=0;j<arr.length;++j) {
let filename = arr[j];
csv()
.fromFile(filename)
.then(reportData => {
if (reportData[0]['Work'].match(shop.productRegex)) {
newArray.push(filename);
}
if (j === arr.length) {
resolve(newArray);
}
});
}
}).then(matches => {
return {
'shop' : shop.name,
'reports' : matches
}
}).catch(e => {
console.log(e);
});
}
Occasionally, the function will output the desired result as shown below:
{ shop: 'shop1',
reports: [ '../artist-sales-report-2020-11-12(1).csv' ] }
{ shop: 'shop2',
reports:
[ '../artist-sales-report-2020-12-03.csv',
'../artist-sales-report-2020-09-01.csv' ] }
However, more often than not, it results in missing reports, like this:
{ shop: 'shop1',
reports: [ '../artist-sales-report-2020-11-12(1).csv' ] }
{ shop: 'shop2',
reports: [ '../artist-sales-report-2020-12-03.csv' ] }
I have identified that the issue lies within the asynchronous nature of the csv reportData block. I have attempted various solutions involving if..then or switch statements to no avail. While creating additional promises within this one may seem cluttered, I have yet to find success with that approach as well.