fix: improve performance of isColor detection (see #378)

Author: josdejong

src/lib/utils/typeUtils.ts

@@ -79,13 +79,15 @@ export function isTimestamp(value: unknown): boolean {
  * Source: https://stackoverflow.com/questions/6386090/validating-css-color-names/33184805
  */
 export function getColorCSS(color: string): string | null {
-  const div = window.document.createElement('div')
+  colorTestDiv = colorTestDiv || window.document.createElement('div')
 
-  div.style.color = color
+  colorTestDiv.style.color = ''
+  colorTestDiv.style.color = color
 
-  const applied = div.style.color
+  const applied = colorTestDiv.style.color
   return applied !== '' ? applied.replace(/\s+/g, '').toLowerCase() : null
 }
+let colorTestDiv: HTMLDivElement | null = null
 
 /**
  * Test if a string contains a valid color name or code.