[Collapsible] Add transition delay (#12118)

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### WHY are these changes introduced?

Part of Shopify/polaris-internal#159

### WHAT is this pull request doing?

Adds a transition delay property. This will be useful while waiting for
the search bar to animate out (top) before collapsing

~~Adds a style prop. Necessary for things like controlling width in a
flex context. I'm not sure we need a full style prop, or classnames, or
just try to limit it to flex grow / shrink. Open to ideas there. This is
a pretty generic container so I don't think allowing a style prop is too
bad.~~

**UPDATE: Opting to override in consumer css instead of adding a style
prop here**

### 🎩 checklist

- [ ] Tested a
[snapshot](https://github.com/Shopify/polaris/blob/main/documentation/Releasing.md#-snapshot-releases)
- [ ] Tested on
[mobile](https://github.com/Shopify/polaris/blob/main/documentation/Tophatting.md#cross-browser-testing)
- [ ] Tested on [multiple
browsers](https://help.shopify.com/en/manual/shopify-admin/supported-browsers)
- [ ] Tested for
[accessibility](https://github.com/Shopify/polaris/blob/main/documentation/Accessibility%20testing.md)
- [ ] Updated the component's `README.md` with documentation changes
- [ ] [Tophatted
documentation](https://github.com/Shopify/polaris/blob/main/documentation/Tophatting%20documentation.md)
changes in the style guide

---------

Co-authored-by: Lo Kim <lo.kim@shopify.com>

.changeset/good-eels-swim.md

@@ -0,0 +1,5 @@
+---
+'@shopify/polaris': minor
+---
+
+Added transition delay to Collapsible

polaris-react/src/components/Collapsible/Collapsible.stories.tsx

@@ -57,6 +57,7 @@ export const Default = {
     );
   },
 };
+
 export const Inline = {
   render() {
     const [open, setOpen] = useState(true);
@@ -70,14 +71,44 @@ export const Inline = {
             <Button
               onClick={handleToggle}
               ariaExpanded={open}
-              ariaControls="basic-collapsible"
+              ariaControls="inline-collapsible"
             >
               Toggle
             </Button>
             <Collapsible open={open} id="inline-collapsible" variant="inline">
-              <p style={{whiteSpace: 'nowrap', backgroundColor: 'red'}}>
-                Non breaking text
-              </p>
+              <p style={{whiteSpace: 'nowrap'}}>Non breaking text</p>
+            </Collapsible>
+          </LegacyStack>
+        </LegacyCard>
+      </div>
+    );
+  },
+};
+
+export const WithDelay = {
+  render() {
+    const [open, setOpen] = useState(true);
+
+    const handleToggle = useCallback(() => setOpen((open) => !open), []);
+
+    return (
+      <div style={{height: '200px'}}>
+        <LegacyCard sectioned>
+          <LegacyStack alignment="center">
+            <Button
+              onClick={handleToggle}
+              ariaExpanded={open}
+              ariaControls="inline-collapsible"
+            >
+              Toggle
+            </Button>
+            <Collapsible
+              open={open}
+              id="inline-collapsible"
+              variant="inline"
+              transition={{delay: '500'}}
+            >
+              <p style={{whiteSpace: 'nowrap'}}>Non breaking text</p>
             </Collapsible>
           </LegacyStack>
         </LegacyCard>
@@ -119,9 +150,7 @@ export const AnimateIn = {
                 duration: 'var(--p-motion-duration-250)',
               }}
             >
-              <p style={{whiteSpace: 'nowrap', backgroundColor: 'red'}}>
-                Non breaking text
-              </p>
+              <p style={{whiteSpace: 'nowrap'}}>Non breaking text</p>
             </Collapsible>
 
             <Button
@@ -141,7 +170,7 @@ export const AnimateIn = {
             <Box maxWidth="20%">
               <Collapsible
                 open={open}
-                id="inline-collapsible"
+                id="basic-collapsible"
                 transition={{
                   animateIn: true,
                   duration: 'var(--p-motion-duration-250)',

polaris-react/src/components/Collapsible/Collapsible.tsx

@@ -1,4 +1,7 @@
 import React, {useState, useRef, useEffect, useCallback} from 'react';
+import type {ReactNode, TransitionEvent} from 'react';
+import {createVar} from '@shopify/polaris-tokens';
+import type {MotionDurationScale} from '@shopify/polaris-tokens';
 
 import {classNames} from '../../utilities/css';
 
@@ -7,6 +10,8 @@ import styles from './Collapsible.module.css';
 interface Transition {
   /** Expand the collpsible on render. */
   animateIn?: boolean;
+  /** Assign a transition delay to the collapsible animation */
+  delay?: MotionDurationScale;
   /** Assign a transition duration to the collapsible animation. */
   duration?: string;
   /** Assign a transition timing function to the collapsible animation */
@@ -31,7 +36,7 @@ export interface CollapsibleProps {
   /** Callback when the animation completes. */
   onAnimationEnd?(): void;
   /** The content to display inside the collapsible. */
-  children?: React.ReactNode;
+  children?: ReactNode;
 }
 
 type AnimationState = 'idle' | 'measuring' | 'animating';
@@ -52,7 +57,6 @@ export function Collapsible({
   const [animationState, setAnimationState] = useState<AnimationState>(
     animateIn ? 'measuring' : 'idle',
   );
-
   const isFullyOpen = animationState === 'idle' && open && isOpen;
   const isFullyClosed = animationState === 'idle' && !open && !isOpen;
   const content = expandOnPrint || !isFullyClosed ? children : null;
@@ -69,6 +73,7 @@ export function Collapsible({
   const transitionDisabled = isTransitionDisabled(transition);
 
   const transitionStyles = typeof transition === 'object' && {
+    transitionDelay: createVar(`motion-duration-${transition.delay ?? '0'}`),
     transitionDuration: transition.duration,
     transitionTimingFunction: transition.timingFunction,
   };
@@ -87,7 +92,7 @@ export function Collapsible({
   };
 
   const handleCompleteAnimation = useCallback(
-    ({target}: React.TransitionEvent<HTMLDivElement>) => {
+    ({target}: TransitionEvent<HTMLDivElement>) => {
       if (target === collapsibleContainer.current) {
         setAnimationState('idle');
         setIsOpen(open);

polaris-react/src/components/Collapsible/tests/Collapsible.test.tsx

@@ -152,7 +152,11 @@ describe('<Collapsible />', () => {
         <Collapsible id="test-collapsible" open transition={{duration}} />,
       );
 
-      expect(collapsible).toHaveReactProps({transition: {duration}});
+      expect(collapsible).toContainReactComponent('div', {
+        style: expect.objectContaining({
+          transitionDuration: duration,
+        }),
+      });
     });
 
     it('passes a timingFunction property', () => {
@@ -165,7 +169,24 @@ describe('<Collapsible />', () => {
         />,
       );
 
-      expect(collapsible).toHaveReactProps({transition: {timingFunction}});
+      expect(collapsible).toContainReactComponent('div', {
+        style: expect.objectContaining({
+          transitionTimingFunction: timingFunction,
+        }),
+      });
+    });
+
+    it('passes a delay property', () => {
+      const delay = '100';
+      const collapsible = mountWithApp(
+        <Collapsible id="test-collapsible" open transition={{delay}} />,
+      );
+
+      expect(collapsible).toContainReactComponent('div', {
+        style: expect.objectContaining({
+          transitionDelay: `var(--p-motion-duration-${delay})`,
+        }),
+      });
     });
 
     const transitionDisabledOptions = [