passport.use(new WeappStrategy({
        appID: {APPID},
        name:{默认为wechat,可以设置组件的名字}
        appSecret: {APPSECRET},
        getToken: {getToken},
        saveToken: {saveToken}
      },
      function(accessToken, refreshToken, profile,expires_in, done) {
        return done(err,profile);
      }
));

The `getToken` and `saveToken` can be provided to initialize Wechat OAuth instance.

router.get("/auth/weapp", passport.authenticate("weapp", options));