AWS signed url if the object exists using promises

I have a code snippet for generating a signed url. The below return statement always returns empty url. Rest of the data is correctly resolved. When I debug I see that the return callback gets executed first then the resolve part of the function validSignedURL gets called.

awsHelper
        .s3vldSignedURL(s3Link)
        .then(function(signedURL) {
            data[1].url = signedURL;
            return callback(null, successResponse.getResponse(context, 'OK', data));
        });

The s3vldSignedURL maps to the function below. Here s3.headobject is promise based, used to check if a file exists in s3. I want this function to be generic, so that I can use it to generate a signed url, for any s3object.

function validSignedURL(bucket, path) {
console.log("Generating Presigned Link ... ");
const s3 = new aws.S3();

let params = {
    Bucket: bucket,
    Key: path
};

let checkObj = s3.getObject(params);
return new Promise(function(resolve, reject){
    s3.headObject(params).promise()
        .then(function (data) {
            console.log('s3 File exists' + data);
            resolve(getSignedURL(bucket, path));
        }).catch(function (err) {
        console.log('Generating Presigned Link ... Failed' + err);
        resolve('');
    });
});
}

The below function getSignedURL always returns a signed url irrespective of the object exists or not.

function getSignedURL(bucket, path) {
    console.log("Generating Presigned Link ... ");
    const s3 = new aws.S3();

    let params = {
        Bucket: bucket,
        Key: path
    };

return s3.getSignedUrl('getObject', params);
}

Also, how can I convert the function call s3.headObject(params) to a synchronous call which returns true or false?

This is the complete function definition and calling for AWS signed url if the object exists using promises. If you are using AWS Lambda you need to add s3 permissions.

If there is no need to validate if the url exists then getSignedURL is the function to be used
If there is a need to check if the object exists then use validSignedURL it will return an empty url if not found.

Here is how I implemented it:

function getSignedURL(bucket, path) {
    console.log("Generating Presigned Link ... ");

    let params = {
        Bucket: bucket,
        Key: path
    };

    //expires in default 15 mins.
    return s3.getSignedUrl('getObject', params);
}

function validSignedURL(bucket, path) {
    console.log("Generating Presigned Link ... ");
    let params = {
        Bucket: bucket,
        Key: path
    };

    return new Promise(function(resolve, reject){
        s3.headObject(params).promise()
            .then(function (data) {
                console.log('s3 File exists' + data);
                resolve(getSignedURL(bucket, path));
            }).catch(function (err) {
            console.log('Generating Presigned Link ... Failed' + err);
            resolve('');
        });
    });
}

Calling the function and resolving the promise. I have some other fields populated before in data which is returned along with the signed url.

    validSignedURL(bucketName, s3Link + fileName).then(function(signedURL) {
        data.url = signedURL;
        return callback(null, successResponse.getResponse(context, 'OK', data));
        });