[fix] Image: image LOADED state is only captured initially

If the Image component is rendered with a `null` source, and consecutively
updated with actual source url that was already loaded, it would fail to
pick up the change - `state` would be `IDLE` for a brief moment and
this would cause a small flicker when the image renders

Let's always start from IDLE state, and update `shouldDisplaySource`
condition to be based on `ImageLoader.has` cache or not

Fix #2492

packages/react-native-web/src/exports/Image/__tests__/__snapshots__/index-test.js.snap

@@ -255,7 +255,7 @@ exports[`components/Image prop "source" is correctly updated when missing in ini
 </div>
 `;
 
-exports[`components/Image prop "source" is not set immediately if the image has not already been loaded 1`] = `
+exports[`components/Image prop "source" is set immediately if the image has already been loaded 1`] = `
 <div
   class="css-view-175oi2r r-flexBasis-1mlwlqe r-overflow-1udh08x r-zIndex-417010"
 >
@@ -272,53 +272,53 @@ exports[`components/Image prop "source" is not set immediately if the image has
 </div>
 `;
 
-exports[`components/Image prop "source" is set immediately if the image has already been loaded 1`] = `
+exports[`components/Image prop "source" is set immediately if the image has already been loaded 2`] = `
 <div
   class="css-view-175oi2r r-flexBasis-1mlwlqe r-overflow-1udh08x r-zIndex-417010"
 >
   <div
     class="css-view-175oi2r r-backgroundColor-1niwhzg r-backgroundPosition-vvn4in r-backgroundRepeat-u6sd8q r-bottom-1p0dtai r-height-1pi2tsx r-left-1d2f490 r-position-u8s1d r-right-zchlnj r-top-ipm5af r-width-13qz1uu r-zIndex-1wyyakw r-backgroundSize-4gszlv"
-    style="background-image: url(https://google.com/favicon.ico);"
+    style="background-image: url(https://twitter.com/favicon.ico);"
   />
   <img
     alt=""
     class="css-accessibilityImage-9pa8cd"
     draggable="false"
-    src="https://google.com/favicon.ico"
+    src="https://twitter.com/favicon.ico"
   />
 </div>
 `;
 
-exports[`components/Image prop "source" is set immediately if the image has already been loaded 2`] = `
+exports[`components/Image prop "source" is set immediately if the image was preloaded 1`] = `
 <div
   class="css-view-175oi2r r-flexBasis-1mlwlqe r-overflow-1udh08x r-zIndex-417010"
 >
   <div
     class="css-view-175oi2r r-backgroundColor-1niwhzg r-backgroundPosition-vvn4in r-backgroundRepeat-u6sd8q r-bottom-1p0dtai r-height-1pi2tsx r-left-1d2f490 r-position-u8s1d r-right-zchlnj r-top-ipm5af r-width-13qz1uu r-zIndex-1wyyakw r-backgroundSize-4gszlv"
-    style="background-image: url(https://twitter.com/favicon.ico);"
+    style="background-image: url(https://yahoo.com/favicon.ico);"
   />
   <img
     alt=""
     class="css-accessibilityImage-9pa8cd"
     draggable="false"
-    src="https://twitter.com/favicon.ico"
+    src="https://yahoo.com/favicon.ico"
   />
 </div>
 `;
 
-exports[`components/Image prop "source" is set immediately if the image was preloaded 1`] = `
+exports[`components/Image prop "source" is set immediately while image is loading and there is no default source 1`] = `
 <div
   class="css-view-175oi2r r-flexBasis-1mlwlqe r-overflow-1udh08x r-zIndex-417010"
 >
   <div
     class="css-view-175oi2r r-backgroundColor-1niwhzg r-backgroundPosition-vvn4in r-backgroundRepeat-u6sd8q r-bottom-1p0dtai r-height-1pi2tsx r-left-1d2f490 r-position-u8s1d r-right-zchlnj r-top-ipm5af r-width-13qz1uu r-zIndex-1wyyakw r-backgroundSize-4gszlv"
-    style="background-image: url(https://yahoo.com/favicon.ico);"
+    style="background-image: url(https://google.com/not-yet-loaded-image.ico);"
   />
   <img
     alt=""
     class="css-accessibilityImage-9pa8cd"
     draggable="false"
-    src="https://yahoo.com/favicon.ico"
+    src="https://google.com/not-yet-loaded-image.ico"
   />
 </div>
 `;

packages/react-native-web/src/exports/Image/__tests__/index-test.js

@@ -277,8 +277,8 @@ describe('components/Image', () => {
       });
     });
 
-    test('is not set immediately if the image has not already been loaded', () => {
-      const uri = 'https://google.com/favicon.ico';
+    test('is set immediately while image is loading and there is no default source', () => {
+      const uri = 'https://google.com/not-yet-loaded-image.ico';
       const source = { uri };
       const { container } = render(<Image source={source} />);
       expect(container.firstChild).toMatchSnapshot();

packages/react-native-web/src/exports/Image/index.js

@@ -225,24 +225,18 @@ const BaseImage: ImageComponent = React.forwardRef((props, ref) => {
     }
   }
 
-  const [state, updateState] = React.useState(() => {
-    const uri = resolveAssetUri(source);
-    if (uri != null) {
-      const isLoaded = ImageLoader.has(uri);
-      if (isLoaded) {
-        return LOADED;
-      }
-    }
-    return IDLE;
-  });
-
+  const [state, updateState] = React.useState(IDLE);
   const [layout, updateLayout] = React.useState({});
   const hasTextAncestor = React.useContext(TextAncestorContext);
   const hiddenImageRef = React.useRef(null);
   const filterRef = React.useRef(_filterId++);
   const requestRef = React.useRef(null);
+  const uri = resolveAssetUri(source);
+  const isCached = uri != null && ImageLoader.has(uri);
   const shouldDisplaySource =
-    state === LOADED || (state === LOADING && defaultSource == null);
+    state === LOADED ||
+    isCached ||
+    (state === LOADING && defaultSource == null);
   const [flatStyle, _resizeMode, filter, _tintColor] = getFlatStyle(
     style,
     blurRadius,
@@ -297,7 +291,6 @@ const BaseImage: ImageComponent = React.forwardRef((props, ref) => {
   }
 
   // Image loading
-  const uri = resolveAssetUri(source);
   React.useEffect(() => {
     abortPendingRequest();