Tutorial: Nested Rows

Nested Rows


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Please note: this feature is in an early development stage. It may not work with some of the plugins and core features. It's not ready for production use.

Overview

The Nested Rows plugin extends Handsontable with a new functionality - displaying nested structures in a two-dimensional data table.

Quick Setup

To enable the plugin, simply set the nestedRows property to true.


hot = new Handsontable(container, {
  data: sourceDataObject,
  rowHeaders: true,
  nestedRows: true,
  contextMenu: true
});
    

Note that using all the functionalities provided by the plugin requires setting rowHeaders (enables the row headers) and contextMenu (enables the Handsontable’s context menu) to true, as the collapse / expand buttons are located in the row headers and row modification options (add row, insert child etc.) are in the Context Menu.

Preparing the data source

The data source has to have a certain structure to be used with the Nested Rows plugin.

The plugin requires the data source to be an array of objects. Each object in the array represents a single 0-level entry. By 0-level I mean an entry which is not a child to any other entry.
If an entry has any child entries, we need to declare them (again) as an array of objects. To assign them to a row, we need to create a __children property in the parent element.

Take a look at this example:

In the example above we’ve created a data object consisting of 2016’s Grammy nominees of the “Rock” genre. As you can see, each 0-level entry declares a category, while their children declare nominees - they’re assigned under the __children properties.

Another thing to mention - the first 0-level object in the array needs to have all columns defined to display the table properly. They can be declared as null or '' (an empty string), but they need to be defined. This is optional for the other objects.

User interface

The Nested Rows plugin user interface is placed in the row headers and the Handsontable’s context menu.

Row headers

Each parent row header contains a +/- button. It is used to collapse or expand its child rows.

Moreover, the child rows’ headers had been given a bigger indentation, so the user can clearly recognize the child and parent elements.

Context Menu

The context menu has been extended with a few Nested Rows-related options, such as:

  • Insert child row
  • Detach from parent

Moreover, the “Insert row above” and “Insert row below” options were modified to work properly with the nested data structure.