Support inserting row/column defs at specific indices rather than always appending

[konossow]

What are you trying to do?

I'm trying to make table with 2 sticky header rows. First row should contain toolbar with table actions, but definition of this row is in separated file, it is passed through cdkTable.addHeaderRowDef . Second row should contain descriptions of columns.

What troubleshooting steps have you tried?

I tried to manually position headerRowDefinition inside _headerRowDefs property, but I'm unable to do that due to:

components/src/cdk/table/table.ts

Line 895 in d3deb8b

this._headerRowDefs = mergeArrayAndSet(

contentHeaderRowDefinitions specified explicit as content are always before customHeaderRowDefinitions added via addHeaderRowDef.

I tried to handle stickness by styling headers postion: sticky and calculate top positioning, but I'm unable to do that due to:

components/src/cdk/table/table.ts

Line 731 in d3deb8b

this._stickyStyler.clearStickyPositioning(headerRows, ['top']);

All header rows have cleared top positioning value that I set via styling.

Reproduction

https://stackblitz.com/edit/angular-bkarpk?file=src/app/table/table.component.html

Environment

• Angular: 11.1.1
• CDK/Material: 11.1.1
• Browser(s): Chrome/Firefox
• Operating System (e.g. Windows, macOS, Ubuntu): Windows

[jelbourn]

To clarify, the issue is that you can't imperatively insert a header row such that it renders above the declarative row?

[konossow]

Exactly!

[jelbourn]

Got it. This is probably a pretty low priority for us, but feel free to send a PR. Off the top of my head, I could see adding an optional index parameter to e.g. addHeaderRowDef as an approach that could work, but looking through the code might bring other ideas to mind

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