new fxpay interface with promises

new-fxpay-interface.js

// Fetch products from the API and also restore products from receipts.
// This used to be fxpay.init() and fxpay.getProducts()
// Old code: 
// https://github.com/mozilla/fxpay/blob/master/example/shared/js/index.js#L41-L50
// https://github.com/mozilla/fxpay/blob/master/example/shared/js/index.js#L249-L257

fxpay.getProducts().then(function(allProducts) {
  allProducts.forEach(function(product) {
    console.log('product ID:', product.id);
    console.log('product name:', product.name);
  
    if (product.receiptExists()) {
      product.validateReceipt().then(function() {
        console.log('product', this, 'can be restored');
      }).catch(function(error) {
        console.error('invalid receipt for installed product:', error);
      });
    } else {
      // Create a purchase button for this product.
    }    
  });
}).catch(function(error) {
  console.error('error getting products:', error);
});


// Purchase a product.
// Old code: https://github.com/mozilla/fxpay/blob/master/example/shared/js/index.js#L125-L134

fxpay.purchase(product.id).then(function(productInfo) {
  console.log('product has been purchased:', productInfo);
}).catch(function(error) {
  console.error('error purchasing product', error.productInfo, 'error:', error);
});


// Validate an app receipt.
// Old code: https://github.com/mozilla/fxpay/blob/master/example/hosted-paid-app/media/js/index.js#L33-L51

fxpay.validateAppReceipt().then(function(receipt) {
  console.log('receipt is valid; app was purchased');
  console.log('product URL:', receipt.productUrl);
  console.log('receipt status:', receipt.validationResult.status);
}).catch(function(error) {
  console.error('error validating receipt:', error);
  var receiptInfo = error.productInfo && error.productInfo.receiptInfo;
  if (receiptInfo.validationResult) {
    console.log('receipt status:', receiptInfo.validationResult.status);
    console.log('receipt status reason:', receiptInfo.validationResult.reason);
  }
});

Re: fxpay.eachProduct() I'm not sure about methods starting with each. I think it makes more sense to have that be fxpay.getProducts().then(function(products){}, function(){})