Below Function converts the Excel sheet (XLSX format) data to JSON. you can add promise to the function.
<script src="https://cdnjs.cloudflare.com/ajax/libs/xlsx/0.8.0/jszip.js"></script>
<script src="https://cdnjs.cloudflare.com/ajax/libs/xlsx/0.8.0/xlsx.js"></script>
<script>
var ExcelToJSON = function() {
this.parseExcel = function(file) {
var reader = new FileReader();
reader.onload = function(e) {
var data = e.target.result;
var workbook = XLSX.read(data, {
type: 'binary'
});
workbook.SheetNames.forEach(function(sheetName) {
// Here is your object
var XL_row_object = XLSX.utils.sheet_to_row_object_array(workbook.Sheets[sheetName]);
var json_object = JSON.stringify(XL_row_object);
console.log(json_object);
})
};
reader.onerror = function(ex) {
console.log(ex);
};
reader.readAsBinaryString(file);
};
};
</script>
Below post has the code for XLS format Excel to JSON javascript code?