Mozilla Parser API is a lot more verbose than XML

ast.json

{
  "type": "Program",
  "body": [
    {
      "type": "VariableDeclaration",
      "declarations": [
        {
          "type": "VariableDeclarator",
          "id": {
            "type": "Identifier",
            "name": "a"
          },
          "init": {
            "type": "ObjectExpression",
            "properties": [
              {
                "type": "Property",
                "key": {
                  "type": "Identifier",
                  "name": "ruby"
                },
                "value": {
                  "type": "Literal",
                  "value": "Ruby",
                  "raw": "\"Ruby\""
                },
                "kind": "init"
              },
              {
                "type": "Property",
                "key": {
                  "type": "Identifier",
                  "name": "cpp"
                },
                "value": {
                  "type": "Literal",
                  "value": "C++",
                  "raw": "\"C++\""
                },
                "kind": "init"
              }
            ]
          }
        }
      ],
      "kind": "var"
    }
  ]
}

generated.js

var a = {
    ruby: 'Ruby',
    cpp: 'C++'
};