This is a PWA (Progressive Web App) written as part of the Andela Learning Community #7DaysOfCodeChallenge.
- Allows the user to select two currencies, enter an amount and convert between them at the current exchange rate.
- Is "installable" by using the "Add to Homescreen" feature in Google Chrome as well as similar features in other browsers and Windows.
- Responsive design that fits well on mobile phones.
- All javascript written in ES6 (gulp/babel used to transform to ES5)
- Working copy hosted on Github Pages
- Serviceworker with caching of pages for offline mode
- IndexedDB for caching exchange rates from CurrencyConverterAPI
The code has intentionally been kept fairly minimal. The purpose is to show off everything written "from scratch" and thus no UI frameworks, app starter kits, etc have been used.
NPM is used for some development dependencies like Gulp and Babel which are used to transform the ES6 code to ES6 so it can be understood by a wider set of browsers.
Jake Archibald's idb library has been used to wrap IndexedDB with an interface supporting Promises.
Express is a simple web server used for testing during development, in order for the service worker to be enabled.
Simply go to https://roryza.github.io/symmetrical-chainsaw/
Clone or download the repo.
Run npm install to restore all dependencies.
Run npm install -g gulp to make sure gulp exists on the path.
Run npm start which will copy some files, transform ES6 -> ES5 and start a small webserver.
Go to http://localhost:3080/ in your browser.
Clone or download the repo. Upload the "/docs" folder to a web host. (the built files are included in the repo for hosting on Github Pages)
Note that the free version of the Currency Converter API supports a maximum of 100 requests per hour. The app will typically only do 1 request for a list of currencies and then one request per currency pair per hour so this means you effectively can't do more than
- The currencies list is only loaded once. Theoretically this could change, and this would require a code change to "refresh"
- The 60 minutes that rates are cached is an approximation of the refreshing on the free API. It is possible a value in the cache is still used when a new rate is available via the API. We could change this to always use the cached rate and then the latest rate however that would increase the number of API requests substantially.
- Their isn't a "friendly" request to refresh dialog when the SW is updated. SW will always skip waiting. Could result in a "double page load" when a user revisits and there have been updates.
- Detect when the user is offline and show a warning
- A "swap" button to swap selections
- Small chart from the history api
- Remember the users last currency selection
- Provide a log/history of conversions (maybe, might clutter simple interface)
- Progress indicator when fetching a rate