How to use the file-type.mime function in file-type

.catch(err => console.error(err));
    }

    if(typeof image === 'string'){
        fs.readFile(image, function(err, buffer){
            if (err) throw err;
            loadImage(buffer, cb);
        });
        return;
    } else if (image instanceof Buffer){
        if (!image.length) {
            console.log("oops");
            return;
        }

        var mime = require('file-type')(image).mime

        if(mime === 'image/png'){
            var PNGReader = require('png.js');
            var reader = new PNGReader(image);
            reader.parse(function(err, png){
                if (err) throw err;

                var image = {
                    width: png.getWidth(),
                    height: png.getHeight()
                }
                image.data = new Uint8Array(image.width * image.height * 4)
                for(var j = 0; j < image.height; j++){
                    for(var i = 0; i < image.width; i++){
                        var offset = 4 * (i + j * image.width),
                            pix = png.getPixel(i, j);