index.js

var FileTransfer = require('NativeModules');
var Sha1 = require('Sha1');

module.exports = {
	config: function(options) {
		/*
			options = {
				apiSecret,
				apiKey,
				cloudName
			}
		*/ 
		this.options = options;
	},

	upload: function (uri, successCb, errorCb) {

		var timestamp = Date.now(),
			keys = "timestamp=" + timestamp + this.options.apiSecret,
			signature = Sha1.hash( keys ),
			obj = {
			    uri: uri,
			    uploadUrl: "https://api.cloudinary.com/v1_1/" + this.options.cloudName + "/image/upload",
			    data: {
			    	api_key: this.options.apiKey,
			    	timestamp: timestamp,
			    	signature: signature
			    }
			};

		FileTransfer.upload(obj, (err, res) => {
			if(res) successCb(res);
		    if(err) errorCb(err);
		});
	}
};