Jest test setup

[1] test-setup.js

require('@testing-library/jest-dom');

// Override.
Object.defineProperty(window, 'requestAnimationFrame', {
    writable: true,
    value: (f) => {
        if (typeof f === 'function') {
            f();
        }
    },
});

[2] package.json

{
  "jest": {
    "moduleFileExtensions": [
      "js",
      "svelte",
      "ts"
    ],
    "setupFilesAfterEnv": [
      "<rootDir>/scripts/test-setup.js"
    ],
    "testEnvironment": "jsdom",
    "transform": {
      "^.+\\.svelte$": [
        "svelte-jester",
        {
          "preprocess": true
        }
      ],
      "^.+\\.ts$": "ts-jest",
      "^.+\\.js$": "babel-jest"
    },
    "transformIgnorePatterns": [
      "<rootDir>/node_modules/lodash-es"
    ]
  }
}