Following Nathan Beck's link sugestion, I used AlaSQL. I'm getting correctly formatted columns, just need to adapt my array to have multiple worksheets.

The way we integrate alaSQL into our Angular project is by including the alasql.min.js and xlsx.core.min.js.

Then we call the alasql method in our function

$scope.export = function(){

var arrayToExport = [{id:1, name:gas},...];

  alasql('SELECT * INTO XLSX(your_filename.xlsx,{headers:true}) FROM ?', arrayToExport);

}

EDIT: Solved the multiple worksheets issues as well. Keep in mind that when using the multiple worksheet method, you have to remove the asterisk and replace the headers: true object in the query with a question mark, passing the options in a separate array. So:

var arrayToExport1 = [{id:1, name:gas},...];

var arrayToExport2 = [{id:1, name:solid},...];

var arrayToExport3 = [{id:1, name:liquid},...];

var finalArray = arrayToExport1.concat(arrayToExport2, arrayToExport3);



var opts = [{sheetid: gas, headers: true},{sheetid: solid, headers: true},{sheetid: liquid, headers: true}];

alasql('SELECT INTO XLSX(your_filename.xlsx,?) FROM ?', [opts, finalArray]);