This example shows how to use the reviver parameter in JSON.parse() to add new object members and format existing members during the parsing phase.
Choose a currency, then get the data
| SKU | Item | Price (USD) | Price (USD) |
|---|---|---|---|
| Click Get Data | |||
The data returned from the server will be a JSON string containing this object structure:
[
{"SKU":"23-23874", "Price":23.99, "Item":"Helmet"},
{"SKU":"48-38835", "Price":14.97, "Item":"Football"},
{"SKU":"84-84848", "Price":3.49, "Item":"Goggles"},
{"SKU":"84-84843", "Price":183, "Item":"Badminton Set"},
{"SKU":"84-39321", "Price":6.79, "Item":"Tennis Balls"},
{"SKU":"39-48949", "Price":618, "Item":"Snowboard"},
{"SKU":"99-28128", "Price":78.99, "Item":"Cleats"},
{"SKU":"83-48281", "Price":4.69, "Item":"Volleyball"},
{"SKU":"89-32811", "Price":0.59, "Item":"Sweatband"},
{"SKU":"28-22847", "Price":779.98, "Item":"Golf Set"},
{"SKU":"38-38281", "Price":8.25, "Item":"Basketball Shorts"},
{"SKU":"82-38333", "Price":1.39, "Item":"Lip balm"},
{"SKU":"21-38485", "Price":0.07, "Item":"Ping Pong ball"},
{"SKU":"83-38285", "Price":3.99, "Item":"Hockey Puck"}
]
reviver function
We'll contain all the moving parts in an example namespace. In it, we'll include the currency exchange rates and a function to reference the rates to add a new member to the JSON response as it is being parsed.
YUI().use("node", "io", "json-parse",function (Y) {
var example = {
rates : {"USD":1,"EUR":0.6661,...,"COP":2000 ,"ARS":3.1289},
currency : 'USD', // updated by the select element
convert : function (k,v) {
// 'this' will refer to the object containing the key:value pair,
// so this step will add a new object member while leaving the original
// intact (but formatted to two decimal places). If the original
// is not needed, just return the converted value.
if (k === 'Price') {
var x = Math.round(v * example.rates[example.currency] * 100) / 100;
this.convertedPrice = x.toFixed(2); // added to item
return v.toFixed(2); // assigned to item.Price
}
return v;
},
…
};
…
When the Get Data button is clicked, we send an io request for the JSON data, and in our success handler, pass our conversion function to JSON.parse() with the response text. The resulting inventory records will have an additional member, convertedPrice. This data is then passed to a UI method to update the inventory table.
Y.one('#demo_go').on('click', function (e) {
// Disable the button temporarily
this.set('disabled',true);
// Store the requested currency
var sel = Y.one("#demo select");
example.currency = sel.get("options").item(sel.get("selectedIndex")).get("value");
// Send the request for the JSON data
Y.io('../assets/json/json-convert-values-response.json',{
timeout : 3000,
on : {
success : function (xid, res) {
var inventory;
try {
inventory = Y.JSON.parse(res.responseText,example.convert);
example.updateTable(inventory);
}
catch(e) {
alert("Error getting inventory data");
}
finally {
Y.one('#demo_go').set('disabled',false);
}
},
failure : function () {
alert("Error getting inventory data");
}
}
});
});
}); // End YUI(..).use(..,function (Y) {
<div id="demo">
<p>Choose a currency, then get the data</p>
<select>
<option value="ARS">Argentine Peso</option>
<option value="AUD">Australian Dollar</option>
<option value="BRL">Brazilian Real</option>
<option value="GBP">British Pound</option>
<option value="CAD">Canadian Dollar</option>
<option value="CNY">Chinese Yuan</option>
<option value="COP">Colombian Peso</option>
<option value="HRK">Croatian Kuna</option>
<option value="CZK">Czech Koruna</option>
<option value="DKK">Danish Krone</option>
<option value="EEK">Estonian Kroon</option>
<option value="EUR">Euro</option>
<option value="HKD">Hong Kong Dollar</option>
<option value="HUF">Hungarian Forint</option>
<option value="ISK">Iceland Krona</option>
<option value="INR">Indian Rupee</option>
<option value="JPY">Japanese Yen</option>
<option value="KRW">Korean Won</option>
<option value="LVL">Latvian Lat</option>
<option value="LTL">Lithuanian Lita</option>
<option value="MYR">Malaysian Ringgit</option>
<option value="MXN">Mexican Peso</option>
<option value="NZD">New Zealand Dollar</option>
<option value="NOK">Norwegian Krone</option>
<option value="PHP">Philippine Peso</option>
<option value="PLN">Polish Zloty</option>
<option value="RUB">Russian Rouble</option>
<option value="SGD">Singapore Dollar</option>
<option value="SKK">Slovak Koruna</option>
<option value="ZAR">South African Rand</option>
<option value="LKR">Sri Lanka Rupee</option>
<option value="SEK">Swedish Krona</option>
<option value="TRY">Turkey Lira</option>
<option value="USD" selected="selected">U.S. Dollar</option>
<option value="CHF">Swiss Franc</option>
<option value="TWD">Taiwan Dollar</option>
<option value="THB">Thai Baht</option>
</select>
<input type="button" id="demo_go" value="Get Data">
<table cellspacing="0">
<caption>Inventory</caption>
<thead>
<tr>
<th>SKU</th>
<th>Item</th>
<th>Price (USD)</th>
<th>Price (<span>USD</span>)</th>
</tr>
</thead>
<tbody>
<tr><td colspan="4">Click <em>Get Data</em></td></tr>
</tbody>
</table>
</div>
<script>
YUI().use("node", "io", "json-parse",function (Y) {
// Safari 4.0.3's native JSON does not support adding members during parse,
// so use JavaScript implementation for consistency
Y.JSON.useNativeParse = false;
var example = {
rates : {"USD":1,"EUR":0.6661,"GBP":0.5207,"AUD":1.1225,"BRL":1.609,"NZD":1.4198,"CAD":1.0667,"CHF":1.0792,"CNY":6.8587 ,"DKK":4.9702,"HKD":7.8064,"INR":42.0168,"JPY":109.8901,"KRW":1000,"LKR":107.5269,"MXN":10.1317,"MYR" :3.3167,"NOK":5.3277,"SEK":6.2617,"SGD":1.4073,"THB":33.7838,"TWD":31.1526,"VEF":2.1445,"ZAR":7.6923 ,"BGN":1.3028,"CZK":16.0514,"EEK":10.4275,"HUF":158.7302,"LTL":2.2999,"LVL":0.4692,"PLN":2.1758,"RON" :2.3804,"SKK":20.2429,"ISK":4.8008,"HRK":81.3008,"RUB":24.3309,"TRY":1.1811,"PHP":44.2478,"COP":2000 ,"ARS":3.1289},
currency : 'USD',
convert : function (k,v) {
// 'this' will refer to the object containing the key:value pair,
// so this step will add a new object member while leaving the original
// intact (but formatted to two decimal places). If the original
// is not needed, just return the converted value.
if (k === 'Price') {
var x = Math.round(v * example.rates[example.currency] * 100) / 100;
this.convertedPrice = x.toFixed(2); // added to item
return v.toFixed(2); // assigned to item.Price
}
return v;
},
updateTable : function (inventory) {
// Update the column header
Y.one('#demo table th span').set('innerHTML',example.currency);
var tbody = Y.one('#demo table tbody'),
html = ['<table><tbody>'],
rowTemplate = '<tr><td>{SKU}</td><td>{Item}</td><td>{Price}</td><td>{convertedPrice}</td></tr>',
i, len;
if (inventory) {
for (i = 0, len = inventory.length; i < len; ++i) {
html.push(Y.Lang.sub(rowTemplate, inventory[i]));
}
} else {
html.push('<tr><td colspan="4">No Inventory data</td></tr>');
}
html.push('</tbody></table>');
tbody.replace(Y.Node.create(html.join('')).one('tbody'));
}
};
Y.one('#demo_go').on('click', function (e) {
// Disable the button temporarily
this.set('disabled',true);
// Store the requested currency
var sel = Y.one("#demo select");
example.currency = sel.get("options").item(sel.get("selectedIndex")).get("value");
Y.io('../assets/json/json-convert-values-response.json',{
timeout : 3000,
on : {
success : function (xid, res) {
var inventory;
try {
inventory = Y.JSON.parse(res.responseText,example.convert);
example.updateTable(inventory);
}
catch(e) {
alert("Error getting inventory data");
}
finally {
Y.one('#demo_go').set('disabled',false);
}
},
failure : function () {
alert("Error getting inventory data");
}
}
});
});
// Expose example objects for inspection
YUI.example = example;
});
</script>