SyntaxError: Cannot use import statement outside a module

I am new to make scripts in Node.js environment. I started to develope GAS application in the environment created by Apps Script in IDE (ASIDE). As I need to use the library Dayjs, I installed that and make scripts according to the official documentation. Then I got the error message "SyntaxError: Cannot use import statement outside a module". If anyone has any information that can help solve this please let me know. More information is below:

index.ts:

import dayjs from 'dayjs';

const now = dayjs();
const date_str = now.format('YYYY/MM/DD HH:mm:ss');

console.log(date_str);

appsscript.json:

{
  "timeZone": "Asia/Tokyo",
  "dependencies": {
  },
  "exceptionLogging": "STACKDRIVER",
  "runtimeVersion": "V8",
  "webapp": {
    "executeAs": "USER_DEPLOYING",
    "access": "ANYONE_ANONYMOUS"
  }
}

package.json:

{
  "name": "gas-sample-2",
  "version": "0.0.0",
  "description": "",
  "main": "build/index.js",
  "license": "Apache-2.0",
  "keywords": [],
  "type": "module",
  "scripts": {
    "clean": "rimraf build dist",
    "lint": "npm run license && eslint --fix --no-error-on-unmatched-pattern src/ test/",
    "bundle": "rollup --no-treeshake -c rollup.config.mjs",
    "build": "npm run clean && npm run bundle && ncp appsscript.json dist/appsscript.json",
    "license": "license-check-and-add add -f license-config.json",
    "test": "jest test/ --passWithNoTests --detectOpenHandles",
    "deploy": "npm run lint && npm run test && npm run build && ncp .clasp-dev.json .clasp.json && clasp push -f && source .env && clasp deploy $DEV_DEPLOYMENT_ID",
    "deploy:prod": "npm run lint && npm run test && npm run build && ncp .clasp-prod.json .clasp.json && clasp push && source .env && clasp deploy $PROD_DEPLOYMENT_ID"
  },
  "engines": {
    "node": ">=12"
  },
  "dependencies": {
    "@google/clasp": "^2.4.2",
    "@types/google-apps-script": "^1.0.83",
    "@types/jest": "^29.5.12",
    "@typescript-eslint/eslint-plugin": "^7.11.0",
    "dayjs": "^1.11.11",
    "eslint": "^8.57.0",
    "eslint-config-prettier": "^9.1.0",
    "eslint-plugin-prettier": "^5.1.3",
    "gts": "^5.3.0",
    "jest": "^29.7.0",
    "license-check-and-add": "^4.0.5",
    "ncp": "^2.0.0",
    "prettier": "^3.2.5",
    "rimraf": "^5.0.7",
    "rollup": "^4.18.0",
    "rollup-plugin-cleanup": "^3.2.1",
    "rollup-plugin-license": "^3.4.0",
    "rollup-plugin-prettier": "^4.1.1",
    "rollup-plugin-typescript2": "^0.36.0",
    "ts-jest": "^29.1.4",
    "typescript": "^5.4.5"
  }
}

tsconfig.json:

{
  "compilerOptions": {
    "target": "ES2022",
    "module": "ES2022",
    "lib": ["ES2022"],
    "sourceMap": true,
    "moduleResolution": "node",
    "outDir": "dist",
    "rootDir": ".",
    "strict": true,
    "esModuleInterop": true,
    "skipLibCheck": true,
    "forceConsistentCasingInFileNames": true,
    "resolveJsonModule": true,
    "allowUnreachableCode": false,
    "allowUnusedLabels": false,
    "allowSyntheticDefaultImports": true,
  },
  "include": ["src/**/*", "test/**/*", "rollup.config.mjs"]
}

iamkun / dayjs

SyntaxError: Cannot use import statement outside a module #2667