运行不起来，打包后没有app.json文件

[firebear]

小程序开发工具报错：VM3706:2 未找到入口 app.json 文件，或者文件读取失败，请检查后重新编译。
目前无头绪，请大家给点线索和思路。

微信开发者工具：v1.02.1807200
node版本：v8.11.3
npm版本：5.6.0

曾经在另外一个项目中发现以下内容放在/src/main.js中export不起作用，改到/src/main.json中可以工作。但是本项目这么改也不起作用。

{
    "pages": [
        "pages/logs/main",
        "^pages/home/main",
        "pages/order/main",
        "pages/my/main",
        "pages/index/main",
        "pages/pay/main"
    ],
    "window": {
        "backgroundTextStyle": "light",
        "navigationBarBackgroundColor": "#fff",
        "navigationBarTitleText": "美团外卖",
        "navigationBarTextStyle": "black"
    },
    "tabBar": {
        "color": "#272636",
        "selectedColor": "#FFD161",
        "backgroundColor": "#fff",
        "borderStyle": "#a8a8a8",
        "list": [
            {
                "pagePath": "pages/home/main",
                "iconPath": "static/images/home.png",
                "selectedIconPath": "static/images/home-selected.png",
                "color": "white",
                "text": "首页"
            },
            {
                "pagePath": "pages/order/main",
                "iconPath": "static/images/order.png",
                "selectedIconPath": "static/images/order-selected.png",
                "text": "订单"
            },
            {
                "pagePath": "pages/my/main",
                "iconPath": "static/images/my.png",
                "selectedIconPath": "static/images/my-selected.png",
                "text": "我的"
            }
        ]
    }
}