fix(ui-truncate-text): parse percentage and non-numeric lineHeight in truncation calc

The v2 truncator treated the lineHeight option as a unitless number and fell back to 1.2
via `options.lineHeight || 1.2`. Percentage values (e.g. "150%") and other string forms
were not handled, so the height budget used for truncation could be wrong.

Accept lineHeight as a string and normalize it: percent values are converted to a unitless
multiplier ("150%" -> 1.5), numeric strings are parsed as-is, and unparsable input falls
back to 1.2. A private options type keeps the internal numeric representation.

Author: HerrTopi

packages/ui-truncate-text/src/TruncateText/v2/utils/truncate.ts

@@ -39,6 +39,10 @@ import { TruncateTextCommonProps } from '../props.js'
 
 export type TruncatorOptions = {
   parent?: Node
+  lineHeight?: string
+} & TruncateTextCommonProps
+
+type PrivateTruncatorOptions = {
   lineHeight?: number
 } & TruncateTextCommonProps
 
@@ -74,7 +78,7 @@ function truncate(element: Element, options?: TruncatorOptions) {
 }
 
 class Truncator {
-  private _options: Required<Omit<TruncatorOptions, 'parent'>> &
+  private _options: Required<PrivateTruncatorOptions> &
     Pick<TruncatorOptions, 'parent'>
   private _stage!: Element
   private _parent?: Node
@@ -89,14 +93,23 @@ class Truncator {
     const parentElement = element?.parentElement
       ? element?.parentElement
       : undefined
+
+    // if a percent, like 100% or 150%, it should be converted to 1 and 1.5 respectively, if a number, we assume a proper lineheight number and if not parsable, it will default to 1.2
+    const lineHeight =
+      options.lineHeight?.slice(-1) === '%'
+        ? Number(options.lineHeight?.slice(0, -1)) / 100
+        : isNaN(Number(options.lineHeight))
+          ? 1.2
+          : Number(options.lineHeight)
+
     this._options = {
       parent: options.parent || parentElement,
       maxLines: options.maxLines || 1,
       position: options.position || 'end',
       truncate: options.truncate || 'character',
       ellipsis: options.ellipsis || '\u2026',
       ignore: options.ignore || [' ', '.', ','],
-      lineHeight: options.lineHeight || 1.2,
+      lineHeight,
       shouldTruncateWhenInvisible: !!options.shouldTruncateWhenInvisible
     }
 
@@ -192,8 +205,8 @@ class Truncator {
                   textContent.match(/.*?[\.\s\/]+?/g)!
                 : ['']
               : shouldTruncate
-              ? node.textContent!.split('')
-              : []
+                ? node.textContent!.split('')
+                : []
         })
       }
     })