message: chartAt returns string
diff: @@ -70,7 +70,7 @@ export default class UPCAReader extends UPCEANReader {
  public maybeReturnResult(result: Result) {
  let text = result.getText();
  - if (text.charAt(0) == '0') {
  + if (text.charAt(0) === '0') {
  let upcaResult = new Result(text.substring(1), null, null, result.getResultPoints(), BarcodeFormat.UPC_A);
  if (result.getResultMetadata() != null) {
  upcaResult.putAllMetadata(result.getResultMetadata());
  