feat(Spinner): make delay customizable

.changeset/rotten-mugs-tan.md

@@ -0,0 +1,5 @@
+---
+'@primer/react': minor
+---
+
+feat: make Spinner's delay customizable

packages/react/src/Spinner/Spinner.docs.json

@@ -33,9 +33,9 @@
     },
     {
       "defaultValue": "false",
-      "description": "Whether to delay the spinner before rendering by the defined 1000ms.",
+      "description": "Controls whether and how long to delay rendering the spinner. Set to `true` to delay by 1000ms, or provide a custom number of milliseconds.",
       "name": "delay",
-      "type": "boolean"
+      "type": "boolean | number"
     }
   ],
   "status": "alpha",

packages/react/src/Spinner/Spinner.test.tsx

@@ -94,5 +94,33 @@ describe('Spinner', () => {
       // No errors should occur
       expect(true).toBe(true)
     })
+
+    it('should render after custom ms when delay is a number', () => {
+      const {container} = render(<Spinner delay={500} />)
+
+      // Not visible initially
+      expect(container.querySelector('svg')).not.toBeInTheDocument()
+
+      // Advance timers by 500ms
+      act(() => {
+        vi.advanceTimersByTime(500)
+      })
+
+      // Now it should be visible
+      expect(container.querySelector('svg')).toBeInTheDocument()
+    })
+
+    it('should cleanup timeout on unmount when delay is a number', () => {
+      const {unmount} = render(<Spinner delay={500} />)
+
+      // Unmount before the delay completes
+      unmount()
+
+      // Advance timers to see if there are any side effects
+      vi.advanceTimersByTime(500)
+
+      // No errors should occur
+      expect(true).toBe(true)
+    })
   })
 })

packages/react/src/Spinner/Spinner.tsx

@@ -23,8 +23,8 @@ export type SpinnerProps = {
   'aria-label'?: string
   className?: string
   style?: React.CSSProperties
-  /** Whether to delay the spinner before rendering by the defined 1000ms. */
-  delay?: boolean
+  /** Controls whether and how long to delay rendering the spinner. Set to `true` to delay by 1000ms, or provide a custom number of milliseconds. */
+  delay?: boolean | number
 } & HTMLDataAttributes
 
 function Spinner({
@@ -46,9 +46,10 @@ function Spinner({
 
   useEffect(() => {
     if (delay) {
+      const delayDuration = typeof delay === 'number' ? delay : 1000
       const timeoutId = setTimeout(() => {
         setIsVisible(true)
-      }, 1000)
+      }, delayDuration)
 
       return () => clearTimeout(timeoutId)
     }