Import

The ImportProducts component uses FileInput to acquire a CSV file, Table to display records as selectable rows, and Queue to import selected rows.

Using FileInput

To exercise XMLUI Invoice's import feature when running the demo app, you'll use FileInput to navigate to products.csv in the app's root folder.
<FileInput
  id="fileInput"
  acceptsFileType="{['.csv']}"
  onDidChange="{ (val) => {
    parsedCsv = window.parseCsv(val[0]).map((item, idx) => {
      return {...item, id: idx};
    });
  }}"
/>

Avoiding duplication

The table that displays imported products makes rows selectable, so you can import only a subset of what's in the CSV file.
It uses rowDisabledPredicate to disable a row if the name of any existing product matches the name of the product in the current row. The function isDuplicate also enables highlighting duplicate rows.
<Table
  id="productsFromCsv"
  data="{ parsedCsv }"
  rowsSelectable="true"
  rowDisabledPredicate="{(row) => isDuplicate(row.name)}"
>
  <Column header="Name">
    <Text color="{isDuplicate($item.name)
        ? '$color-danger-500' : '$textColor-primary'}"
    >
      {$item.name} {isDuplicate($item.name) ? '(duplicate)' : ''}
    </Text>
  </Column>
  <Column bindTo="description"/>
  <Column bindTo="price"/>
</Table>
We define isDuplicate() using a <script> helper tag.
<Component name="ImportProducts">
  <script>
    function isDuplicate(name) {
      return existingProducts.value.some(p => p.name === name);
    }
  </script>
  <!-- ... -->
</Component>

Using Queue

The API doesn't support batch update so we use Queue to iterate over the selected rows and make an APICall for each.
<Queue id="importQueue" clearAfterFinish="true">
  <property name="progressFeedback">
    <Text value="Importing {
      pluralize(importQueue.getQueuedItems().length, 'product', 'products')
    }"/>
  </property>
  <property name="resultFeedback">
    <Text value="Imported {pluralize($completedItems.length,
      'product', 'products')}"
    />
  </property>
  <event name="process">
    <APICall
      url="/api/products"
      method="post"
      body="{$param.item}"
    />
  </event>
  <event name="complete" value="productsFromCsv.clearSelection()"/>
</Queue>
pluralize is a global helper function.
The import button uses the queue's enqueueItems method to populate the queue with the result of the table's getSelectedItems method.
<Button
  label="Import"
  onClick="{ importQueue.enqueueItems(productsFromCsv.getSelectedItems())}"
  enabled="{productsFromCsv.getSelectedItems().length}"
/>