Image prefetch does not work on iOS

[rossjohnsonMP]

Please provide all the information requested. Issues that do not follow this format are likely to stall.

Description

• Using image prefetch does not work at all on iOS.
• Preloading the images and then checking Image.queryCache shows an empty query cache
• Attempting to display images that have been prefetched using cache: 'only-if-cached' will result in no image shown
• Works absolutely fine on Android
• There are a number of other issues reporting the same thing in the past this one and another
• https://www.npmjs.com/package/react-native-fast-image provides the same behaviour so perhaps this isn't getting much traction but I'm keen to not add on libraries for something that is supposed to be supported

React Native version:

System:
OS: macOS 10.15.3
CPU: (4) x64 Intel(R) Core(TM) i7-7660U CPU @ 2.50GHz
Memory: 289.63 MB / 16.00 GB
Shell: 3.2.57 - /bin/bash
Binaries:
Node: 10.16.3 - /usr/local/opt/node@10/bin/node
Yarn: 1.15.2 - ~/.yarn/bin/yarn
npm: 6.9.0 - /usr/local/opt/node@10/bin/npm
Watchman: 4.9.0 - /usr/local/bin/watchman
Managers:
CocoaPods: 1.9.1 - /usr/local/bin/pod
SDKs:
iOS SDK:
Platforms: iOS 13.2, DriverKit 19.0, macOS 10.15, tvOS 13.2, watchOS 6.1
Android SDK:
API Levels: 28
Build Tools: 28.0.3
System Images: android-29 | Google Play Intel x86 Atom
Android NDK: Not Found
IDEs:
Android Studio: 3.3 AI-182.5107.16.33.5199772
Xcode: 11.3/11C29 - /usr/bin/xcodebuild
Languages:
Java: 1.8.0_192 - /usr/bin/javac
Python: 2.7.16 - /usr/bin/python
npmPackages:
@react-native-community/cli: Not Found
react: 16.11.0 => 16.11.0
react-native: 0.62.1 => 0.62.1
npmGlobalPackages:
react-native: Not Found

Steps To Reproduce

Provide a detailed list of steps that reproduce the issue.

1. Preload an image using Image.prefetch(img)
2. display the image using only-if-cached

OR

1. Preload an image using Image.prefetch(img)
2. display the image

Expected Results

Scenario 1

1. Image is shown

Scenario 1

1. Image is instantly shown

Snack, code example, screenshot, or link to a repository:

https://snack.expo.io/yseyl0_9N

[darcoola]

I have the same problem using simulators. It works for Android but not for iOS.

[martin-888]

Just confirming same problem on iOS.

[CDBridger]

I am seeing the same, can anyone recommend an alternative library which supports prefetching in the meantime (which is not dead)?

[rossjohnsonMP]

I am seeing the same, can anyone recommend an alternative library which supports prefetching in the meantime (which is not dead)?

@CDBridger I found that react-native-fast-image is broken in the opposite way and seems like its dying so not the best alternative

[giaset]

Having the exact same issue on iOS. Prefetching all my images but getting an empty cache when I call Image.queryCache

Obviously, this causes only-if-cached to not work either

[nhohb]

Same issue on iOS when offline mode

[JackClown]

same problem
react-native: 0.59.10

[Twinski]

Can confirm this on RN 0.61.4!
Interesting discovery: the Image.queryCache does show images which are smaller in size..

Measured behavior:
Loading large images (eg. Unsplash wallpapers ~1.3MB): no file stored in the fsCachedData folder
Loading normal size images (~200KB): file stored in fsCachedData & appears in Image.queryCache

[punjasin]

same here it take sometimes for image to load up even queryCache show that image are already cache