json-convert-values.mustache revision 312e93cdc4550ab4fd4a833d88e25e7915a54a8a
<div class="intro">
<p>
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.
</p>
</div>
<div class="example">
{{>json-convert-values-source}}
</div>
<h2>The Data</h2>
<p>
The data returned from the server will be a JSON string containing this object structure:
</p>
```json
[
{"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"}
]
```
<h2>Create a `reviver` function</h2>
<p>
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.
</p>
```
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') {
this.convertedPrice = x.toFixed(2); // added to item
return v.toFixed(2); // assigned to item.Price
}
return v;
},
…
};
…
```
<h2>Sending the request and parsing the JSON response</h2>
<p>
When the <em>Get Data</em> 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.
</p>
```
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");
// Send the request for the JSON data
Y.io('{{componentAssets}}/json-convert-values-response.json',{
timeout : 3000,
on : {
success : function (xid, res) {
var inventory;
try {
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) {
```
<h2>Complete Example Source</h2>
```
{{>json-convert-values-source}}
```