read csv in javascript

index.tsx
function handleFiles(files) {
  // Check for the various File API support.
  if (window.FileReader) {
    // FileReader are supported.
    getAsText(files[0]);
  } else {
    alert('FileReader are not supported in this browser.');
  }
}

function getAsText(fileToRead) {
  var reader = new FileReader();
  // Read file into memory as UTF-8.
  reader.readAsText(fileToRead);
  // Handle errors load.
  reader.onload = function(event) {
    var csv = event.target.result;
    processData(csv);
  };
  reader.onerror = function() {
    alert('Unable to read ' + fileToRead.fileName);
  };
}

function processData(csv) {
  var allTextLines = csv.split(/\r\n|\n/);
  var headers = allTextLines[0].split(',');
  var lines = [];

  for (var i = 1; i < allTextLines.length; i++) {
    var data = allTextLines[i].split(',');
    if (data.length == headers.length) {
      var line = {};
      for (var j = 0; j < headers.length; j++) {
        line[headers[j]] = data[j];
      }
      lines.push(line);
    }
  }
  // do something with the lines array
}
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