[8.0.0+] toHTML() returns an error if only colHeaders or rowHeaders are on

[AMBudnik]

Description

The toHTML() returns an error if colHeaders are on in versions 8+

Steps to reproduce

1. Go to https://jsfiddle.net/handsoncode/bqepxasw/ (7.4.2.)
2. Log result
   
3. Go to https://jsfiddle.net/handsoncode/3mg8rsxc/ (8.0.0)
4. Log result
   

Details

• it works well if we turn off both - column and row headers https://jsfiddle.net/handsoncode/021Lp9jd/1/
• it breaks for only colHeaders or only rowHeaders https://jsfiddle.net/handsoncode/k46vr73o/

Demo

https://jsfiddle.net/handsoncode/1efLzgu7/ 7.4.2 - last working
https://jsfiddle.net/handsoncode/3mg8rsxc/ 8.0.0 - first broken
https://jsfiddle.net/handsoncode/6ua5efqr/ - (current) 8.4.0 - still broken

Your environment

• Handsontable version: 8+
• Browser Name and version: Chrome 89
• Operating System: Windows 10

[aninde]

This issue will be fixed by v9.0.2
Demo https://jsfiddle.net/zd2cL7gh/

Result from v9.0.2:
<table><thead><tr><th>A</th><th>B</th><th>C</th></tr></thead><tbody><tr><td >3</td><td >5</td><td >6</td></tr><tr><td >6</td><td >7</td><td >9</td></tr></tbody></table>

[mrpiotr-dev]

I'm happy to announce we just released v9.0.2 with the fix to this bug.