refactor(Collapse): streamline atom functions

change/@fluentui-react-motion-components-preview-67537ce1-b461-4bec-bbcb-61d9202e6632.json

@@ -0,0 +1,7 @@
+{
+  "type": "patch",
+  "comment": "refactor(Collapse): streamline atom functions",
+  "packageName": "@fluentui/react-motion-components-preview",
+  "email": "robertpenner@microsoft.com",
+  "dependentChangeType": "patch"
+}

packages/react-components/react-motion-components-preview/library/src/atoms/fade-atom.ts

@@ -0,0 +1,33 @@
+import { AtomMotion, PresenceDirection, motionTokens } from '@fluentui/react-motion';
+
+interface FadeAtomParams {
+  direction: PresenceDirection;
+  duration: number;
+  easing?: string;
+  fromValue?: number;
+}
+
+/**
+ * Generates a motion atom object for a fade in or fade out.
+ * @param direction - The functional direction of the motion: 'enter' or 'exit'.
+ * @param duration - The duration of the motion in milliseconds.
+ * @param easing - The easing curve for the motion. Defaults to `motionTokens.curveLinear`.
+ * @param fromValue - The starting opacity value. Defaults to 0.
+ * @returns A motion atom object with opacity keyframes and the supplied duration and easing.
+ */
+export const fadeAtom = ({
+  direction,
+  duration,
+  easing = motionTokens.curveLinear,
+  fromValue = 0,
+}: FadeAtomParams): AtomMotion => {
+  const keyframes = [{ opacity: fromValue }, { opacity: 1 }];
+  if (direction === 'exit') {
+    keyframes.reverse();
+  }
+  return {
+    keyframes,
+    duration,
+    easing,
+  };
+};

packages/react-components/react-motion-components-preview/library/src/components/Collapse/Collapse.ts

@@ -1,14 +1,8 @@
 import { motionTokens, createPresenceComponent, AtomMotion } from '@fluentui/react-motion';
 import type { PresenceMotionFnCreator } from '../../types';
 import type { CollapseDelayedVariantParams, CollapseRuntimeParams, CollapseVariantParams } from './collapse-types';
-import {
-  sizeEnterAtom,
-  whitespaceEnterAtom,
-  opacityEnterAtom,
-  opacityExitAtom,
-  sizeExitAtom,
-  whitespaceExitAtom,
-} from './collapse-atoms';
+import { sizeEnterAtom, sizeExitAtom, whitespaceAtom } from './collapse-atoms';
+import { fadeAtom } from '../../atoms/fade-atom';
 
 /** Define a presence motion for collapse/expand that can stagger the size and opacity motions by a given delay. */
 export const createCollapseDelayedPresence: PresenceMotionFnCreator<
@@ -32,52 +26,29 @@ export const createCollapseDelayedPresence: PresenceMotionFnCreator<
     // ----- ENTER -----
     // The enter transition is an array of up to 3 motion atoms: size, whitespace and opacity.
     const enterAtoms: AtomMotion[] = [
-      sizeEnterAtom({
-        orientation,
-        duration: enterSizeDuration,
-        easing: enterEasing,
-        element,
-      }),
-      whitespaceEnterAtom({
-        orientation,
-        duration: enterSizeDuration,
-        easing: enterEasing,
-      }),
+      sizeEnterAtom({ orientation, duration: enterSizeDuration, easing: enterEasing, element }),
+      whitespaceAtom({ direction: 'enter', orientation, duration: enterSizeDuration, easing: enterEasing }),
     ];
     // Fade in only if animateOpacity is true. Otherwise, leave opacity unaffected.
     if (animateOpacity) {
-      enterAtoms.push(
-        opacityEnterAtom({
-          duration: enterOpacityDuration,
-          easing: enterEasing,
-          delay: enterDelay,
-        }),
-      );
+      enterAtoms.push({
+        ...fadeAtom({ direction: 'enter', duration: enterOpacityDuration, easing: enterEasing }),
+        delay: enterDelay,
+        fill: 'both',
+      });
     }
 
     // ----- EXIT -----
     // The exit transition is an array of up to 3 motion atoms: opacity, size and whitespace.
     const exitAtoms: AtomMotion[] = [];
     // Fade out only if animateOpacity is true. Otherwise, leave opacity unaffected.
     if (animateOpacity) {
-      exitAtoms.push(
-        opacityExitAtom({
-          duration: exitOpacityDuration,
-          easing: exitEasing,
-        }),
-      );
+      exitAtoms.push(fadeAtom({ direction: 'exit', duration: exitOpacityDuration, easing: exitEasing }));
     }
     exitAtoms.push(
-      sizeExitAtom({
-        orientation,
-        duration: exitSizeDuration,
-        easing: exitEasing,
-        element,
-        delay: exitDelay,
-      }),
-    );
-    exitAtoms.push(
-      whitespaceExitAtom({
+      sizeExitAtom({ orientation, duration: exitSizeDuration, easing: exitEasing, element, delay: exitDelay }),
+      whitespaceAtom({
+        direction: 'exit',
         orientation,
         duration: exitSizeDuration,
         easing: exitEasing,

packages/react-components/react-motion-components-preview/library/src/components/Collapse/collapse-atoms.ts

@@ -1,5 +1,5 @@
-import { AtomMotion } from '@fluentui/react-motion/src/types';
-import type { CollapseOrientation } from './collapse-types';
+import { AtomMotion, PresenceDirection } from '@fluentui/react-motion';
+import { CollapseOrientation } from './collapse-types';
 
 // ----- SIZE -----
 
@@ -11,19 +11,21 @@ const sizeValuesForOrientation = (orientation: CollapseOrientation, element: Ele
   return { sizeName, overflowName, toSize };
 };
 
+interface SizeEnterAtomParams {
+  orientation: CollapseOrientation;
+  duration: number;
+  easing: string;
+  element: HTMLElement;
+  fromSize?: string;
+}
+
 export const sizeEnterAtom = ({
   orientation,
   duration,
   easing,
   element,
   fromSize = '0',
-}: {
-  orientation: CollapseOrientation;
-  duration: number;
-  easing: string;
-  element: HTMLElement;
-  fromSize?: string;
-}): AtomMotion => {
+}: SizeEnterAtomParams): AtomMotion => {
   const { sizeName, overflowName, toSize } = sizeValuesForOrientation(orientation, element);
 
   return {
@@ -37,21 +39,18 @@ export const sizeEnterAtom = ({
   };
 };
 
+interface SizeExitAtomParams extends SizeEnterAtomParams {
+  delay?: number;
+}
+
 export const sizeExitAtom = ({
   orientation,
   duration,
   easing,
   element,
   delay = 0,
   fromSize = '0',
-}: {
-  orientation: CollapseOrientation;
-  duration: number;
-  easing: string;
-  element: HTMLElement;
-  delay?: number;
-  fromSize?: string;
-}): AtomMotion => {
+}: SizeExitAtomParams): AtomMotion => {
   const { sizeName, overflowName, toSize } = sizeValuesForOrientation(orientation, element);
 
   return {
@@ -88,82 +87,34 @@ const whitespaceValuesForOrientation = (orientation: CollapseOrientation) => {
   };
 };
 
-// Because a height of zero does not eliminate padding or margin,
-// we will create keyframes to animate them to zero.
-export const whitespaceEnterAtom = ({
-  orientation,
-  duration,
-  easing,
-}: {
+interface WhitespaceAtomParams {
+  direction: PresenceDirection;
   orientation: CollapseOrientation;
   duration: number;
   easing: string;
-}): AtomMotion => {
-  const { paddingStart, paddingEnd, marginStart, marginEnd } = whitespaceValuesForOrientation(orientation);
-  return {
-    // Animate from whitespace of zero to the current whitespace, by omitting the ending keyframe.
-    keyframes: [{ [paddingStart]: '0', [paddingEnd]: '0', [marginStart]: '0', [marginEnd]: '0', offset: 0 }],
-    duration,
-    easing,
-  };
-};
+  delay?: number;
+}
 
-export const whitespaceExitAtom = ({
+export const whitespaceAtom = ({
+  direction,
   orientation,
   duration,
   easing,
   delay = 0,
-}: {
-  orientation: CollapseOrientation;
-  duration: number;
-  easing: string;
-  delay?: number;
-}): AtomMotion => {
+}: WhitespaceAtomParams): AtomMotion => {
   const { paddingStart, paddingEnd, marginStart, marginEnd } = whitespaceValuesForOrientation(orientation);
-  return {
-    // Animate from the current whitespace to whitespace of zero, by using offset 1 and omitting the starting keyframe.
-    keyframes: [{ [paddingStart]: '0', [paddingEnd]: '0', [marginStart]: '0', [marginEnd]: '0', offset: 1 }],
+  // The keyframe with zero whitespace is at the start for enter and at the end for exit.
+  const offset = direction === 'enter' ? 0 : 1;
+  const keyframes = [{ [paddingStart]: '0', [paddingEnd]: '0', [marginStart]: '0', [marginEnd]: '0', offset }];
+
+  const atom: AtomMotion = {
+    keyframes,
     duration,
     easing,
-    fill: 'forwards',
     delay,
   };
+  if (direction === 'exit') {
+    atom.fill = 'forwards';
+  }
+  return atom;
 };
-
-// ----- OPACITY -----
-
-export const opacityEnterAtom = ({
-  duration,
-  easing,
-  delay = 0,
-  fromOpacity = 0,
-  toOpacity = 1,
-}: {
-  duration: number;
-  easing: string;
-  delay?: number;
-  fromOpacity?: number;
-  toOpacity?: number;
-}): AtomMotion => ({
-  keyframes: [{ opacity: fromOpacity }, { opacity: toOpacity }],
-  duration,
-  easing,
-  delay,
-  fill: 'both',
-});
-
-export const opacityExitAtom = ({
-  duration,
-  easing,
-  fromOpacity = 0,
-  toOpacity = 1,
-}: {
-  duration: number;
-  easing: string;
-  fromOpacity?: number;
-  toOpacity?: number;
-}): AtomMotion => ({
-  keyframes: [{ opacity: toOpacity }, { opacity: fromOpacity }],
-  duration,
-  easing,
-});