Filter Data on Map and then Export Filtered Data to CSV

[RezaTehranifar2]

I have an application that has filter widgets that interacts with the map on the page. The client would now like to be able to export the data to csv. I am a little tight in space I dont want nor need to see the data in a table. Has someone created a widget that does this? I dont think I found one yet but I will continue looking while I wait for responses.
Is there a hack? Ideally I just want a button that says export to csv.

[JeffreyThompson2 · Accepted solution]

function customExportCSV() {
    let query = featureLayer.createQuery()
    query.where = '1=1'
    let csv = ''
    let headers = ''

    featureLayer.queryFeatures(query).then((featureSet) => {
        headers = Object.keys(featureSet.features[0].attributes).join(',')

        for (let i = 0; i < featureSet.features.length; i++) {
            const data = Object.values(featureSet.features[i].attributes).join(',')
            csv += data + '\n'
        }

        csv = headers + '\n' + csv

        downloadCSV(csv)
    })   
}   

function downloadCSV(csv) {
    const csvFile = new Blob([csv], { type: 'text/csv' });
    const downloadLink = document.createElement("a");
    downloadLink.download = 'search_results.csv';
    downloadLink.href = window.URL.createObjectURL(csvFile);
    downloadLink.style.display = "none";

    document.body.appendChild(downloadLink);
    downloadLink.click();
}  

Here's my function for downloading a csv from a FeatureLayer.

[RezaTehranifar2]

This is great. Thanks!

This is assuming there is only one layer in the map. Correct? My map has multiple layers.

[JeffreyThompson2]

It will download data from whatever feature layer is assigned to the variable featureLayer. To make it more flexible, make featureLayer a parameter of the customExportCSV function, then create another function that finds a feature layer from a user input and calls customExportCSV(featureLayer).

[RezaTehranifar2]

Thanks. I am so so on JS, so I may hardcoded as you have it above at first, but I will work on the additional code to make it for flexible. Thank you for the outline of that part.