未知原因调用var函数

我有下面的代码,它似乎调用 var promiseFeedback 我不知道为什么。。。这意味着即使在创建文档时发生错误,也会调用它。然而,只有在没有 err

有人能弄清楚原因吗?

if (json) {
    createDocument(documentUrl, context, json, function(res){
    var promiseFeedback = callFB (context, res);
    var collection = `mydb`

    client.createDocument(collection, res, (err, result) => {
        if(err) {
            context.log(err);
            return context.done();
        } else {
            Promise.all([promiseFeedback]).then(function(results){ 
            context.log("promiseFeedback: " + results[0]);
            context.done();
            });
        }
    });
    });
}
function callFB(context, res) {
        return new Promise((resolve, reject) => {

        var requestUrl = url.parse( URL );
            var requestBody = {
                "id": res.id
            };

            var body = JSON.stringify( requestBody );

            const requestOptions = {
                hostname: requestUrl.hostname,
                path: requestUrl.path,
                method: 'POST',
                headers: {
                'Content-Type': 'application/json',
                'Content-Length': Buffer.byteLength(body),
                }
            };

            var request = https.request(requestOptions, function(res) {
                var data ="";
                res.on('data', function (chunk) {
                    data += chunk
                });
                res.on('end', function () {
                resolve(true);
                })
            }).on('error', function(error) {
                context.log("request error:", error);
                resolve(false);
            });
            request.write(body);
            request.end();
            });    
}