[docs] Mention row id requirement and document getRowId prop

[cherniavskii]

Currently DataGrid throws an error if row doesn't have an id property.
This is not documented though, and there's getRowId prop that can be used instead.
I've updated the error message to mention getRowId prop as well.

Preview: https://deploy-preview-3765--material-ui-x.netlify.app/components/data-grid/rows/

[mui-bot]

These are the results for the performance tests:

Test case	Unit	Min	Max	Median	Mean	σ
Filter 100k rows	ms	1,110.8	1,753.4	1,146.1	1,377.38	305.756
Sort 100k rows	ms	676.2	1,083.7	1,083.7	915.68	166.41
Select 100k rows	ms	141.8	298.2	234.4	227.92	53.04
Deselect 100k rows	ms	91.8	176.7	151.4	139	27.63

Generated by 🚫 dangerJS against f0d6354

[cherniavskii]

Well, it looks like it's not up to me to decide whether there's demo preview or not 😀
docs:typescript:formatted generates preview automatically if it's short enough (currently maxLines is 16).
I guess I'm keeping the preview then.

[flaviendelangle]

@cherniavskii here is an example with the code not expanded by default:

{{"demo": "pages/components/data-grid/filtering/BasicExampleDataGrid.js", "bg": "inline", "defaultCodeOpen": false}}

[m4theushw]

We could also mention that the "id" property doesn't need to be specified in the columns prop. An user wasn't aware of this: #346 (comment)

[flaviendelangle]

Something like this ?

⚠️ Each row should have a unique id even when no there is no id column

[cherniavskii]

Interesting. Looks like the issue here is understanding columns - users might think that every field in their rows data is required to be reflected in columns as well.
Maybe instead we should mention on Columns page that it's not required for columns to cover all the fields available in rows data?

[cherniavskii]

It could be, but then we would need to say there that, although the "id" is required, a "id" column is not.

Now I'm convinced to your initial proposal - I'll mention id column here :)

[cherniavskii]

I tried to make it as clear as I could and ended up with this:

Note that column definition for id field is not required.

[cherniavskii]

@flaviendelangle interesting, I did not expect this setting to toggle demo code preview!
I guess demo preview is still generated by the script, but it will not be shown. I'll use that, thanks!