How to use the kinvey-nativescript-sdk.Files function in kinvey-nativescript-sdk

this.uploadImage = function (remoteFullPath, localFullPath) {
        const imageFile = fs.File.fromPath(localFullPath);
        const imageContent = imageFile.readSync();

        const metadata = {
            filename: imageFile.name,
            mimeType: this._getMimeType(imageFile.extension),
            size: imageContent.length,
            public: true
        };

        return Kinvey.Files.upload(imageFile, metadata, { timeout: 2147483647 })
            .then((uploadedFile) => {
                const query = new Kinvey.Query();
                query.equalTo("_id", uploadedFile._id);

                return Kinvey.Files.find(query);
            })
            .then((files) => {
                if (files && files.length) {
                    const file = files[0];
                    file.url = file._downloadURL;

                    return file;
                } else {
                    Promise.reject(new Error("No items with the given ID could be found."));
                }
            });

.then((uploadedFile) => {
                const query = new Kinvey.Query();
                query.equalTo("_id", uploadedFile._id);

                return Kinvey.Files.find(query);
            })
            .then((files) => {