Error with code example in tutorial

Using this tutorial there is a small error that we got stuck on in part 4.

We ended up editing it this way I am sure something more elegant is what you guys had in mind. This is just an example.

function TodoBlock() {
    // YOUR CODE GOES HERE
    const base = useBase();
    const globalConfig = useGlobalConfig();
    const tableId = globalConfig.get('selectedTableId');
    const completedFieldId = globalConfig.get('completedFieldId');
    const table = base.getTableByIdIfExists(tableId);
    const completedField = table ? table.getFieldByIdIfExists(completedFieldId) : null;
    const toggle = (record) => {
        table.updateRecordAsync(
            record, {[completedFieldId]: !record.getCellValue(completedField)}
        );
    };    
    const records = useRecords(table);
    const tasks = records && completedField ? records.map(record => (
        <Task key={record.id} record={record} onToggle={toggle} completedFieldId={completedField} />
   )) : null;
    return (
        <div>
            <TablePickerSynced globalConfigKey="selectedTableId" />
            <FieldPickerSynced table={table} globalConfigKey="completedFieldId" />
            {tasks}
        </div>
    )
}