Set up Unit Test for typescript/react

jest.config.js

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+module.exports = {
+    // The root of your source code, typically /src
+    // `<rootDir>` is a token Jest substitutes
+    roots: ["<rootDir>/src"],
+
+    // Jest transformations -- this adds support for TypeScript
+    // using ts-jest
+    transform: {
+      '^.+\\.tsx?$': 'ts-jest',
+      ".+\\.(css|styl|less|sass|scss)$": "jest-transform-css"
+    },
+
+    // Runs special logic, such as cleaning up components
+    // when using React Testing Library and adds special
+    // extended assertions to Jest
+    setupFilesAfterEnv: [
+      "@testing-library/jest-dom/extend-expect"
+    ],
+
+    // Test spec file resolution pattern
+    // Matches parent folder `__tests__` and filename
+    // should contain `test` or `spec`.
+    testRegex: "(/__tests__/.*|(\\.|/)(test|spec))\\.tsx?$",
+
+    // Module file extensions for importing
+    moduleFileExtensions: ["ts", "tsx", "js", "jsx", "json", "node"],
+
+  };