运行脚本时缺少 NPM 命令

Question

我有这个 package.json 文件：

{
  "name": "ztm-stripe-app",
  "version": "1.0.0",
  "engines": {
    "node": "12.18.3",
    "npm": "6.14.6"
  },
  "scripts": {
    "client": "cd client && npm start",
    "server": "nodemon server.js",
    "build": "cd client && npm run build",
    "dev": "concurrently --kill-others-on-fail \"npm server\" \"npm client\"",
    "start": "node server.js",
    "heroku-postbuild": "cd client && npm install && npm install --only=dev --no-shrinkwrap && npm run build"
  },
  "dependencies": {
    "body-parser": "^1.19.0",
    "compression": "^1.7.4",
    "concurrently": "^6.2.0",
    "dotenv": "^10.0.0",
    "express": "^4.17.1",
    "nodemon": "^2.0.12",
    "stripe": "^8.161.0"
  }
}

当我运行 npm run dev 时，我收到一条错误消息，指出同时不是 NPM 命令。当我检查 node_modules 文件夹时，我可以看到它确实在本地和全局安装。

有什么想法吗？