Transform photo with imagemin before uploading to s3 using multer-s3-transform

I was trying to use multer-s3-transform in uploading my photo to s3, but before that I need to transform the image to much lower file size using imagemin. I was able to do it using sharp but still want to try it using imagemin to specifically set the quality.

This is what I did using sharp. I need to find a way how to do it using imagemin

const multerS3Obj = multerS3({
    s3 : s3,
    bucket : config.amazon.s3.bucketName,
    acl : "public-read",
    contentType : multerS3.AUTO_CONTENT_TYPE,
    metadata : function(req, file, cb) {
        const metadataObj = Object.assign({}, req.body);

        metadataObj.content_type = file.mimetype;
        metadataObj.filename = file.originalname;

        cb(null, metadataObj);
    },
    shouldTransform: function(req, file, cb) {
        cb(null, /^image/i.test(file.mimetype));
    },
    transforms: [
        {
          key: function(req, file, cb) {
            const refType = req.params.refType,
                refId = req.params.refId,
                subfolder = `uploads/${refType}/${refId}/`;
                cb(null, subfolder + file.originalname);
          },
          transform: function(req, file, cb) {
            cb(null, sharp().resize(null,null));
          }
        }
    ]
});

This is what I did using imagemin but it didn't work

const buff = async (image, path) => {
    const files = await imagemin([image], path, {
        plugins : [
            imageminJpegtran(),
            imageminPngquant({quality: '65-80'})
        ]
    })
}

this is the transform part in the first code

transform: async function(req, file, cb) {
    const files = await buff(file.originalname, 'location')
    cb(null, sharp().resize(null,null));
}

I keep getting error: uncaughtException: dest.on is not a function

I was able to solved it. instead of using imagemin to set the quality of the image found out that sharp supports setting of image quality

let quality = ''
if (file.mimetype === 'image/jpeg') {
    quality = sharp().jpeg({quality: 50})
} else if (file.mimetype === 'image/png') {
    quality = sharp().png({quality: 50})
}