docs(examples): helper lines (#1915)

feat: add optional chaining to prevent types errors and add an example of helper lines (#1904)

* docs: code errors in "Updating Node Data" (#1900)

fix(docs): Example of fixing code errors in "Updating Node Data"

* fix: add optional chaining to prevent errors in link filtering

* feat: add an example of helper lines

* refactor: In the HelperLines example, replace the observer with dimensions

---------

Co-authored-by: Charles Lee <114982593+rookie-orange@users.noreply.github.com>
Co-authored-by: J <gongjie0422@163.com>

docs/examples/helper-lines/index.ts

@@ -0,0 +1,5 @@
+export { default as HelperLinesApp } from './App.vue?raw'
+export { default as HelperLinesUtils } from './utils.ts?raw'
+export { default as HelperLinesInitialElements } from './initialElements.ts?raw'
+export { default as HelperLinesStyle } from './style.css?inline'
+export { default as HelperLinesComponent } from './HelperLines.vue?raw'