1

I have a very simple array that I'd like to export to CSV: 

var uniqueCounties = ["555","123","345"];

I have tried using methods found online but I have been getting various errors, and all the methods online deal with nested arrays.

My function at the moment is converting to a string. I was hoping it would simplify the process but I'm still now sure how to progress:

function download_csv() {
        var csv = uniqueCounties.toString();
        console.log(csv);
    }

I was originally trying this method: 

uniqueCounties.forEach(function(infoArray, index){

   dataString = infoArray.join(",");
   csvContent += index < data.length ? dataString+ "\n" : dataString;

});

But kept getting the error infoArray.join is not a function.

sparta93
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Matthew Snell
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1 Answers1

2

If you have a 2d array of strings (or anything that you are ok with toString-ing) for example:

const input = [
  ["555","123","345"],
  [1, 2, 3],
  [true, false, "foo"]
]

Then you can do something like this:

function toCsv(input) {
  return input.map(row => row.join(',')).join('\n')
}

const csvString = toCsv(input)

Resulting in this string:

555,123,345
1,2,3
true,false,foo

If you just want to convert a single 1d array to csv, like in the example then:

const uniqueCounties = ["555","123","345"]

// If you want each value as a column
const csvAsSingleRow = uniqueCounties.join(',')

// If you want each value as a row
const csvAsSingleColumn = uniqueCounties.join('\n')

This gets more and more complicated if you want to include escaping, etc... In that case I'd recommend looking for a library that does this well.

Balázs Édes
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  • Thanks for the reply! I went with the `csvAsSingleRow` approach and had it `console.log` the output. Would it be difficult from here to download this as a CSV file? – Matthew Snell Mar 30 '17 at 17:03
  • Not sure what do you mean by download. Do you run this in the browser or node? – Balázs Édes Mar 30 '17 at 18:07
  • It's ran in the browser. The idea is someone can map counties (hence the uniqueCounties variable). And then export the selection to a file on their computer. – Matthew Snell Mar 30 '17 at 18:09
  • See this answer for that http://stackoverflow.com/a/14966131/1126273 You have to either encode it as an URI along with the information of what file type it is and call `window.open` with the string, or create a link. The answer explains both nicely. – Balázs Édes Mar 31 '17 at 07:32