use typescript

package.json

@@ -30,5 +30,12 @@
       "last 1 firefox version",
       "last 1 safari version"
     ]
+  },
+  "devDependencies": {
+    "@types/jest": "^26.0.15",
+    "@types/node": "^14.14.2",
+    "@types/react": "^16.9.53",
+    "@types/react-dom": "^16.9.8",
+    "typescript": "^4.0.3"
   }
 }

src/App.tsx

@@ -1,6 +1,6 @@
 import React from 'react';
 
-function App() {
+const App = () =>{
   return (
     <div >
       Hello

src/react-app-env.d.ts

@@ -0,0 +1 @@
+/// <reference types="react-scripts" />

tsconfig.json

@@ -0,0 +1,25 @@
+{
+  "compilerOptions": {
+    "target": "es5",
+    "lib": [
+      "dom",
+      "dom.iterable",
+      "esnext"
+    ],
+    "allowJs": true,
+    "skipLibCheck": true,
+    "esModuleInterop": true,
+    "allowSyntheticDefaultImports": true,
+    "strict": true,
+    "forceConsistentCasingInFileNames": true,
+    "module": "esnext",
+    "moduleResolution": "node",
+    "resolveJsonModule": true,
+    "isolatedModules": true,
+    "noEmit": true,
+    "jsx": "react"
+  },
+  "include": [
+    "src"
+  ]
+}

yarn.lock

@@ -1561,6 +1561,14 @@
   dependencies:
     "@types/istanbul-lib-report" "*"
 
+"@types/jest@^26.0.15":
+  version "26.0.15"
+  resolved "https://registry.yarnpkg.com/@types/jest/-/jest-26.0.15.tgz#12e02c0372ad0548e07b9f4e19132b834cb1effe"
+  integrity sha512-s2VMReFXRg9XXxV+CW9e5Nz8fH2K1aEhwgjUqPPbQd7g95T0laAcvLv032EhFHIa5GHsZ8W7iJEQVaJq6k3Gog==
+  dependencies:
+    jest-diff "^26.0.0"
+    pretty-format "^26.0.0"
+
 "@types/json-schema@^7.0.3":
   version "7.0.4"
   resolved "https://registry.yarnpkg.com/@types/json-schema/-/json-schema-7.0.4.tgz#38fd73ddfd9b55abb1e1b2ed578cb55bd7b7d339"
@@ -1581,6 +1589,11 @@
   resolved "https://registry.yarnpkg.com/@types/node/-/node-13.9.2.tgz#ace1880c03594cc3e80206d96847157d8e7fa349"
   integrity sha512-bnoqK579sAYrQbp73wwglccjJ4sfRdKU7WNEZ5FW4K2U6Kc0/eZ5kvXG0JKsEKFB50zrFmfFt52/cvBbZa7eXg==
 
+"@types/node@^14.14.2":
+  version "14.14.2"
+  resolved "https://registry.yarnpkg.com/@types/node/-/node-14.14.2.tgz#d25295f9e4ca5989a2c610754dc02a9721235eeb"
+  integrity sha512-jeYJU2kl7hL9U5xuI/BhKPZ4vqGM/OmK6whiFAXVhlstzZhVamWhDSmHyGLIp+RVyuF9/d0dqr2P85aFj4BvJg==
+
 "@types/parse-json@^4.0.0":
   version "4.0.0"
   resolved "https://registry.yarnpkg.com/@types/parse-json/-/parse-json-4.0.0.tgz#2f8bb441434d163b35fb8ffdccd7138927ffb8c0"
@@ -1596,14 +1609,14 @@
   resolved "https://registry.yarnpkg.com/@types/q/-/q-1.5.2.tgz#690a1475b84f2a884fd07cd797c00f5f31356ea8"
   integrity sha512-ce5d3q03Ex0sy4R14722Rmt6MT07Ua+k4FwDfdcToYJcMKNtRVQvJ6JCAPdAmAnbRb6CsX6aYb9m96NGod9uTw==
 
-"@types/react-dom@*":
+"@types/react-dom@*", "@types/react-dom@^16.9.8":
   version "16.9.8"
   resolved "https://registry.yarnpkg.com/@types/react-dom/-/react-dom-16.9.8.tgz#fe4c1e11dfc67155733dfa6aa65108b4971cb423"
   integrity sha512-ykkPQ+5nFknnlU6lDd947WbQ6TE3NNzbQAkInC2EKY1qeYdTKp7onFusmYZb+ityzx2YviqT6BXSu+LyWWJwcA==
   dependencies:
     "@types/react" "*"
 
-"@types/react@*":
+"@types/react@*", "@types/react@^16.9.53":
   version "16.9.53"
   resolved "https://registry.yarnpkg.com/@types/react/-/react-16.9.53.tgz#40cd4f8b8d6b9528aedd1fff8fcffe7a112a3d23"
   integrity sha512-4nW60Sd4L7+WMXH1D6jCdVftuW7j4Za6zdp6tJ33Rqv0nk1ZAmQKML9ZLD4H0dehA3FZxXR/GM8gXplf82oNGw==
@@ -3690,6 +3703,11 @@ diff-sequences@^24.9.0:
   resolved "https://registry.yarnpkg.com/diff-sequences/-/diff-sequences-24.9.0.tgz#5715d6244e2aa65f48bba0bc972db0b0b11e95b5"
   integrity sha512-Dj6Wk3tWyTE+Fo1rW8v0Xhwk80um6yFYKbuAxc9c3EZxIHFDYwbi34Uk42u1CdnIiVorvt4RmlSDjIPyzGC2ew==
 
+diff-sequences@^26.5.0:
+  version "26.5.0"
+  resolved "https://registry.yarnpkg.com/diff-sequences/-/diff-sequences-26.5.0.tgz#ef766cf09d43ed40406611f11c6d8d9dd8b2fefd"
+  integrity sha512-ZXx86srb/iYy6jG71k++wBN9P9J05UNQ5hQHQd9MtMPvcqXPx/vKU69jfHV637D00Q2gSgPk2D+jSx3l1lDW/Q==
+
 diffie-hellman@^5.0.0:
   version "5.0.3"
   resolved "https://registry.yarnpkg.com/diffie-hellman/-/diffie-hellman-5.0.3.tgz#40e8ee98f55a2149607146921c63e1ae5f3d2875"
@@ -5816,6 +5834,16 @@ jest-diff@^24.0.0, jest-diff@^24.9.0:
     jest-get-type "^24.9.0"
     pretty-format "^24.9.0"
 
+jest-diff@^26.0.0:
+  version "26.6.0"
+  resolved "https://registry.yarnpkg.com/jest-diff/-/jest-diff-26.6.0.tgz#5e5bbbaf93ec5017fae2b3ef12fc895e29988379"
+  integrity sha512-IH09rKsdWY8YEY7ii2BHlSq59oXyF2pK3GoK+hOK9eD/x6009eNB5Jv1shLMKgxekodPzLlV7eZP1jPFQYds8w==
+  dependencies:
+    chalk "^4.0.0"
+    diff-sequences "^26.5.0"
+    jest-get-type "^26.3.0"
+    pretty-format "^26.6.0"
+
 jest-docblock@^24.3.0:
   version "24.9.0"
   resolved "https://registry.yarnpkg.com/jest-docblock/-/jest-docblock-24.9.0.tgz#7970201802ba560e1c4092cc25cbedf5af5a8ce2"
@@ -5874,6 +5902,11 @@ jest-get-type@^24.9.0:
   resolved "https://registry.yarnpkg.com/jest-get-type/-/jest-get-type-24.9.0.tgz#1684a0c8a50f2e4901b6644ae861f579eed2ef0e"
   integrity sha512-lUseMzAley4LhIcpSP9Jf+fTrQ4a1yHQwLNeeVa2cEmbCGeoZAtYPOIv8JaxLD/sUpKxetKGP+gsHl8f8TSj8Q==
 
+jest-get-type@^26.3.0:
+  version "26.3.0"
+  resolved "https://registry.yarnpkg.com/jest-get-type/-/jest-get-type-26.3.0.tgz#e97dc3c3f53c2b406ca7afaed4493b1d099199e0"
+  integrity sha512-TpfaviN1R2pQWkIihlfEanwOXK0zcxrKEE4MlU6Tn7keoXdN6/3gK/xl0yEh8DOunn5pOVGKf8hB4R9gVh04ig==
+
 jest-haste-map@^24.9.0:
   version "24.9.0"
   resolved "https://registry.yarnpkg.com/jest-haste-map/-/jest-haste-map-24.9.0.tgz#b38a5d64274934e21fa417ae9a9fbeb77ceaac7d"
@@ -8343,7 +8376,7 @@ pretty-format@^25.1.0:
     ansi-styles "^4.0.0"
     react-is "^16.12.0"
 
-pretty-format@^26.4.2:
+pretty-format@^26.0.0, pretty-format@^26.4.2, pretty-format@^26.6.0:
   version "26.6.0"
   resolved "https://registry.yarnpkg.com/pretty-format/-/pretty-format-26.6.0.tgz#1e1030e3c70e3ac1c568a5fd15627671ea159391"
   integrity sha512-Uumr9URVB7bm6SbaByXtx+zGlS+0loDkFMHP0kHahMjmfCtmFY03iqd++5v3Ld6iB5TocVXlBN/T+DXMn9d4BA==
@@ -10136,6 +10169,11 @@ typedarray@^0.0.6:
   resolved "https://registry.yarnpkg.com/typedarray/-/typedarray-0.0.6.tgz#867ac74e3864187b1d3d47d996a78ec5c8830777"
   integrity sha1-hnrHTjhkGHsdPUfZlqeOxciDB3c=
 
+typescript@^4.0.3:
+  version "4.0.3"
+  resolved "https://registry.yarnpkg.com/typescript/-/typescript-4.0.3.tgz#153bbd468ef07725c1df9c77e8b453f8d36abba5"
+  integrity sha512-tEu6DGxGgRJPb/mVPIZ48e69xCn2yRmCgYmDugAVwmJ6o+0u1RI18eO7E7WBTLYLaEVVOhwQmcdhQHweux/WPg==
+
 unicode-canonical-property-names-ecmascript@^1.0.4:
   version "1.0.4"
   resolved "https://registry.yarnpkg.com/unicode-canonical-property-names-ecmascript/-/unicode-canonical-property-names-ecmascript-1.0.4.tgz#2619800c4c825800efdd8343af7dd9933cbe2818"