Fix FastImage preload error
1 min read

Fix FastImage preload error

With [react-native-fast-image](https://github.com/DylanVann/react-native-fast-image), you can preload images like this:

import FastImage from 'react-native-fast-image';

FastImage.preload([
  {
    uri: 'https://facebook.github.io/react/img/logo_og.png',
    headers: {Authorization: 'someAuthToken'},
  },
]);

But after integrated, yarn test yelled at me:

TypeError: Cannot read property 'preload' of undefined

A quick Google search didn't give me anything useful, but I noticed it's similar to another issue I came across before:

// Fix: "TypeError: Cannot read property 'DocumentDir' of undefined"
// https://github.com/wkh237/react-native-fetch-blob/issues/212#issuecomment-308182094
jest.mock('rn-fetch-blob', () => {
  return {
    DocumentDir: () => {},
    polyfill: () => {},
  };
});

So I tried this, it works.

// Fix: "TypeError: Cannot read property 'preload' of undefined"
jest.mock('react-native-fast-image', () => {
  return {
    preload: () => {},
  };
});