feat: support creating containers, linear elements, text containers, labelled arrows and arrow bindings programatically (#6546)

* feat: support creating text containers programatically

* fix

* fix

* fix

* fix

* update api to use label

* fix api and support individual shapes and text element

* update test case in package example

* support creating arrows and line

* support labelled arrows

* add in package example

* fix alignment

* better types

* fix

* keep element as is unless we support prog api

* fix tests

* fix lint

* ignore

* support arrow bindings via start and end in api

* fix lint

* fix coords

* support id as well for elements

* preserve bindings if present and fix testcases

* preserve bindings for labelled arrows

* support ids, clean up code and move the api related stuff to transform.ts

* allow multiple arrows to bind to single element

* fix singular elements

* fix single text element, unique id and tests

* fix lint

* fix

* support binding arrow to text element

* fix creation of regular text

* use same stroke color as parent for text containers and height 0 for linear element by default

* fix types

* fix

* remove more ts ignore

* remove ts ignore

* remove

* Add coverage script

* Add tests

* fix tests

* make type optional when id present

* remove type when id provided in tests

* Add more tests

* tweak

* let host call convertToExcalidrawElements when using programmatic API

* remove convertToExcalidrawElements call from restore

* lint

* update snaps

* Add new type excalidraw-api/clipboard for programmatic api

* cleanup

* rename tweak

* tweak

* make image attributes optional and better ts check

* support image via programmatic API

* fix lint

* more types

* make fileId mandatory for image and export convertToExcalidrawElements

* fix

* small tweaks

* update snaps

* fix

* use Object.assign instead of mutateElement

* lint

* preserve z-index by pushing all elements first and then add bindings

* instantiate instead of closure for storing elements

* use element API to create regular text, diamond, ellipse and rectangle

* fix snaps

* udpdate api

* ts fixes

* make `convertToExcalidrawElements` more typesafe

* update snaps

* refactor the approach so that order of elements doesn't matter

* Revert "update snaps"

This reverts commit 621dfadccf.

* review fixes

* rename ExcalidrawProgrammaticElement -> ExcalidrawELementSkeleton

* Add tests

* give preference to first element when duplicate ids found

* use console.error

---------

Co-authored-by: dwelle <luzar.david@gmail.com>

src/utils.ts

@@ -914,3 +914,16 @@ export const isOnlyExportingSingleFrame = (
     )
   );
 };
+
+export const assertNever = (
+  value: never,
+  message: string,
+  softAssert?: boolean,
+): never => {
+  if (softAssert) {
+    console.error(message);
+    return value;
+  }
+
+  throw new Error(message);
+};