[TS migration] Setup typescript in expensify-common & Migrate CONST, fastMerge, Device, Logger to Typescript

.eslintignore

@@ -1 +1,4 @@
 *.d.ts
+dist
+node_modules
+*.config.js

.eslintrc.js

@@ -1,11 +1,72 @@
 module.exports = {
     extends: ['expensify', 'prettier'],
-    rules: {
-        // Allow JSX to be written in any file ignoring the extension type
-        'react/jsx-filename-extension': 'off'
-    },
-    plugins: ['jest'],
-    env: {
-        "jest/globals": true
-    }
+    parser: '@typescript-eslint/parser',
+    overrides: [
+        {
+            files: ['*.js', '*.jsx'],
+            settings: {
+                'import/resolver': {
+                    node: {
+                        extensions: ['.js', '.jsx', '.ts', '.tsx'],
+                    },
+                },
+            },
+            rules: {
+                // Allow JSX to be written in any file ignoring the extension type
+                'react/jsx-filename-extension': 'off',
+                'rulesdir/no-api-in-views': 'off',
+                'rulesdir/no-multiple-api-calls': 'off',
+                'rulesdir/prefer-import-module-contents': 'off',
+                'no-constructor-return': 'off',
+                'import/extensions': [
+                    'error',
+                    'ignorePackages',
+                    {
+                        js: 'never',
+                        jsx: 'never',
+                        ts: 'never',
+                        tsx: 'never',
+                    },
+                ],
+            },
+        },
+        {
+            files: ['*.ts', '*.tsx'],
+            extends: ['expensify', 'plugin:@typescript-eslint/recommended', 'plugin:@typescript-eslint/stylistic', 'plugin:import/typescript', 'prettier', 'plugin:prettier/recommended'],
+            plugins: ['react', 'import', '@typescript-eslint'],
+            parserOptions: {
+                project: './tsconfig.json',
+            },
+            rules: {
+                'prefer-regex-literals': 'off',
+                'rulesdir/prefer-underscore-method': 'off',
+                'react/jsx-props-no-spreading': 'off',
+                'react/require-default-props': 'off',
+                'valid-jsdoc': 'off',
+                'es/no-optional-chaining': 'off',
+                'es/no-nullish-coalescing': 'off',
+                'react/jsx-filename-extension': ['error', {extensions: ['.tsx', '.jsx']}],
+                'import/no-unresolved': 'error',
+                'import/consistent-type-specifier-style': ['error', 'prefer-top-level'],
+                'no-use-before-define': 'off',
+                '@typescript-eslint/no-use-before-define': 'off',
+                '@typescript-eslint/no-unused-vars': ['error', {argsIgnorePattern: '^_'}],
+                '@typescript-eslint/consistent-type-imports': ['error', {prefer: 'type-imports'}],
+                '@typescript-eslint/consistent-type-exports': ['error', {fixMixedExportsWithInlineTypeSpecifier: false}],
+                '@typescript-eslint/no-non-null-assertion': 'off',
+                '@typescript-eslint/array-type': ['error', {default: 'array-simple'}],
+                '@typescript-eslint/consistent-type-definitions': 'off',
+                'import/extensions': [
+                    'error',
+                    'ignorePackages',
+                    {
+                        js: 'never',
+                        jsx: 'never',
+                        ts: 'never',
+                        tsx: 'never',
+                    },
+                ],
+            },
+        },
+    ],
 };

.github/workflows/lint.yml

@@ -27,3 +27,12 @@ jobs:
             - run: npm run lint
               env:
                   CI: true
+
+            - name: Verify there's no Prettier diff
+              run: |
+                  npm run prettier -- --loglevel silent
+                  if ! git diff --name-only --exit-code; then
+                    # shellcheck disable=SC2016
+                    echo 'Error: Prettier diff detected! Please run `npm run prettier` and commit the changes.'
+                    exit 1
+                  fi

.github/workflows/typecheck.yml

@@ -0,0 +1,24 @@
+name: TypeScript Checks
+
+on:
+    pull_request:
+        types: [opened, synchronize]
+
+jobs:
+    lint:
+        runs-on: ubuntu-latest
+        steps:
+            - uses: actions/checkout@v4
+
+            - name: Setup Node
+              uses: actions/setup-node@v4
+              with:
+                  cache: npm
+                  cache-dependency-path: package-lock.json
+
+            - run: npm ci
+
+            - name: Type check with TypeScript
+              run: npm run typecheck
+              env:
+                  CI: true

.gitignore

@@ -5,3 +5,4 @@ npm-debug.log
 package.json-e
 .DS_Store
 *.swp
+dist

.prettierignore

@@ -0,0 +1,4 @@
+dist
+package.json
+package-lock.json
+*.html

babel.config.js

@@ -1,12 +1,3 @@
 module.exports = {
-    presets: [
-        [
-            '@babel/preset-env',
-            {
-                targets: {
-                    node: 'current',
-                },
-            },
-        ],
-    ],
+    presets: [['@babel/preset-env', {targets: {node: 'current'}}], '@babel/preset-typescript'],
 };

lib/API.jsx

@@ -150,6 +150,7 @@ export default function API(network, args) {
      * @param {String} commandName The name of the API command
      */
     function requireParameters(parameterNames, parameters, commandName) {
+        // eslint-disable-next-line rulesdir/prefer-early-return
         parameterNames.forEach((parameterName) => {
             if (!_(parameters).has(parameterName) || parameters[parameterName] === null || parameters[parameterName] === undefined) {
                 const parametersCopy = _.clone(parameters);
@@ -823,7 +824,7 @@ export default function API(network, args) {
              *
              * @returns {APIDeferred}
              */
-            createAdminIssuedVirtualCard: function (parameters) {
+            createAdminIssuedVirtualCard(parameters) {
                 const commandName = 'Card_CreateAdminIssuedVirtualCard';
                 requireParameters(['cardTitle', 'assigneeEmail', 'cardLimit', 'cardLimitType', 'domainName'], parameters, commandName);
                 return performPOSTRequest(commandName, parameters);
@@ -842,7 +843,7 @@ export default function API(network, args) {
              *
              * @returns {APIDeferred}
              */
-            editAdminIssuedVirtualCard: function (parameters) {
+            editAdminIssuedVirtualCard(parameters) {
                 const commandName = 'Card_EditAdminIssuedVirtualCard';
                 requireParameters(['domainName', 'cardID', 'cardTitle', 'assigneeEmail', 'cardLimit', 'cardLimitType'], parameters, commandName);
                 return performPOSTRequest(commandName, parameters);