Error: number or rows selected on custom single selected row

[0xj0hnny]

Hi,

First of all, great job on implemented this library. Since the table does not support single row select. I have to implemented some custom code to enforce the single select for the table. Below are the code that I implemented.

customToolbarSelect: (selectedRows) => {
            const newSelectedRow = selectedRows.data.length > 1 ? selectedRows.data[1] : selectedRows.data[0];
            const newSelectedIndex = parseInt(newSelectedRow.index);
            const temp = {
              data: newSelectedRow,
              lookup: {}
            };
            temp.lookup[`${newSelectedIndex}`] = true;
            if (selectedRows.data.length > 1) {
              selectedRows.data = [];
              selectedRows.lookup = temp.lookup;
              selectedRows.data.push(temp.data);
            }
          }
},
  ....

Expected Behavior

I expected that the number or `rows selected` on Toolbar would be either 0, or 1. 

Current Behavior

If I selected one row and then select another, the number of rows selected is 2, instead of 1. And unless I deselect the selected row to clear out the number. The number of rows selected stays at 2.

Steps to Reproduce (for bugs)

Your Environment

Tech	Version
Material-UI	3.5.1
MUI-datatables	2.0.0-beta-41
React	16.6.0
browser	Chrome

[gregnb]

If you want to implement this in the library I would accept a PR for the following:

In the component's options, one should be able to set

Name	Type	Default	Description
selectableRows	string	'multiple'	Configure row selection. Options: 'single', 'multiple' or 'false'

When "single" is selected:

• It will not render checkboxes
• Rows are selectable but only single selection
• Selected row is highlighted

When "multiple" is selected:

• It will render checkboxes
• Rows are selectable
• Selected row is highlighted

When "false" is selected:

• It will not render checkboxes
• Rows are not selectable

[viniciusalvess]

Just a fix on @johnnyliang213 's code. But that was a nice enhancement suggestion, thank you.

const newSelectedRow = selectedRows.data[selectedRows.data.length -1]; // selectedRows.data.length > 1 ? selectedRows.data[1] : selectedRows.data[0];
const newSelectedIndex = parseInt(newSelectedRow.index);
const temp = {
    data: newSelectedRow,
    lookup: {}
};

temp.lookup[`${newSelectedIndex}`] = true;
//if (selectedRows.data.length > 1) {
selectedRows.data = [];
selectedRows.lookup = temp.lookup;
selectedRows.data = temp.data; //selectedRows.data.push(temp.data);
//}