tsconfig.json

{
    "extends": "@tsconfig/svelte/tsconfig.json",
    "compilerOptions": {
        "target": "esnext",
        "useDefineForClassFields": true,
        "module": "esnext",
        "resolveJsonModule": true,
        "baseUrl": ".",
        /**
         * Typecheck JS in `.svelte` and `.js` files by default.
         * Disable checkJs if you'd like to use dynamic types in JS.
         * Note that setting allowJs false does not prevent the use
         * of JS in `.svelte` files.
         */
        "allowJs": true,
        "checkJs": true,
        "strict": true,
        "noUnusedParameters": true,
        "noUnusedLocals": true,
        "noImplicitReturns": true,
        "noFallthroughCasesInSwitch": true,
        "noUncheckedIndexedAccess": true,
        "noPropertyAccessFromIndexSignature": true,
        "noImplicitOverride": true,
        "exactOptionalPropertyTypes": true,
        "types": ["cypress", "@testing-library/cypress", "jest", "@types/jest"]
    },
    "include": ["src/**/*.d.ts", "src/**/*.ts", "src/**/*.js", "src/**/*.svelte"]
}