[fix] SSR of Image renders source

When rendered on the server, images now include the 'src' and will be
downloaded by the browser rather than waiting for the client-side JS to
initiate image loading.

Fix #543

src/components/Image/__tests__/index-test.js

@@ -1,10 +1,12 @@
 /* eslint-env jasmine, jest */
 
+import ExecutionEnvironment from 'fbjs/lib/ExecutionEnvironment';
 import Image from '../';
 import ImageUriCache from '../ImageUriCache';
 import React from 'react';
 import { mount, render } from 'enzyme';
 
+const originalCanUseDOM = ExecutionEnvironment.canUseDOM;
 const originalImage = window.Image;
 
 describe('components/Image', () => {
@@ -113,6 +115,15 @@ describe('components/Image', () => {
       ImageUriCache.remove(uriTwo);
       expect(component.render().find('img').attr('src')).toBe(uriTwo);
     });
+
+    test('is set immediately when rendered on the server', () => {
+      ExecutionEnvironment.canUseDOM = false;
+      const uri = 'https://google.com/favicon.ico';
+      const component = render(<Image source={{ uri }} />);
+      expect(component.find('img').attr('src')).toBe(uri);
+      expect(ImageUriCache.has(uri)).toBe(true);
+      ExecutionEnvironment.canUseDOM = originalCanUseDOM;
+    });
   });
 
   describe('prop "style"', () => {

src/components/Image/index.js

@@ -11,6 +11,7 @@
  */
 
 import applyNativeMethods from '../../modules/applyNativeMethods';
+import { canUseDOM } from 'fbjs/lib/ExecutionEnvironment';
 import createDOMElement from '../../modules/createDOMElement';
 import ImageLoader from '../../modules/ImageLoader';
 import ImageResizeMode from './ImageResizeMode';
@@ -41,8 +42,8 @@ const ImageSourcePropType = oneOfType([
   string
 ]);
 
-const getImageState = (uri, isPreviouslyLoaded) => {
+const getImageState = (uri, shouldDisplaySource) => {
-  return isPreviouslyLoaded ? STATUS_LOADED : uri ? STATUS_PENDING : STATUS_IDLE;
+  return shouldDisplaySource ? STATUS_LOADED : uri ? STATUS_PENDING : STATUS_IDLE;
 };
 
 const resolveAssetDimensions = source => {
@@ -111,10 +112,10 @@ class Image extends Component {
     super(props, context);
     // If an image has been loaded before, render it immediately
     const uri = resolveAssetSource(props.source);
-    const isPreviouslyLoaded = ImageUriCache.has(uri);
+    const shouldDisplaySource = ImageUriCache.has(uri) || !canUseDOM;
-    this.state = { shouldDisplaySource: isPreviouslyLoaded };
+    this.state = { shouldDisplaySource };
-    this._imageState = getImageState(uri, isPreviouslyLoaded);
+    this._imageState = getImageState(uri, shouldDisplaySource);
-    isPreviouslyLoaded && ImageUriCache.add(uri);
+    shouldDisplaySource && ImageUriCache.add(uri);
   }
 
   componentDidMount() {