How to append a attribute to already existing JSON using node js

Question

How to append a attribute to already existing JSON using node js

I have a JSON as follows:

{
      "elements": [
      {
        "name": "F975CFAF-8FB4-2926-DD56-74CD230D15AF",
        "uri": "vm/hpcloud/nova/large",
        "parameters": {
          "imageUri": "image/hpcloud/nova/ami-00001b03",
          "securityGroups": [
            "default"
          ]
        },
        "metadata": {
          "name": "HPCloud Large VM with Ubuntu 10.04 With BitNami WebPack 1.2-0 Nova",
          "description": "HPCloud Large VM with Ubuntu 10.04 With BitNami WebPack 1.2-0 Nova"
        }
      }
      ]
}

I need to manipulate the attribute "metadata" as follows (note that new attribute is appended) :

{
      "elements": [
      {
        "name": "F975CFAF-8FB4-2926-DD56-74CD230D15AF",
        "uri": "vm/hpcloud/nova/large",
        "parameters": {
          "imageUri": "image/hpcloud/nova/ami-00001b03",
          "securityGroups": [
            "default"
          ]
        },
        "metadata": {
          "name": "HPCloud Large VM with Ubuntu 10.04 With BitNami WebPack 1.2-0 Nova",
          "description": "HPCloud Large VM with Ubuntu 10.04 With BitNami WebPack 1.2-0 Nova",
          "charge" : 80
        }
      }
      ]
}

Any straightforward way to accomplish this using node js?

javascript
json
node.js

Answer 1

Assuming that you really mean a JavaScript object, use this:

obj.elements[0].metadata.charge = 80;

If you really mean JSON, than parse it before and encode it afterwards again:

obj = JSON.parse( json );
obj.elements[0].metadata.charge = 80;
json = JSON.stringify( obj );