{
  "type": "Script",
  "span": {
    "start": 19,
    "end": 83,
    "ctxt": 0
  },
  "body": [
    {
      "type": "FunctionDeclaration",
      "identifier": {
        "type": "Identifier",
        "span": {
          "start": 36,
          "end": 37,
          "ctxt": 0
        },
        "value": "f",
        "optional": false
      },
      "declare": true,
      "params": [],
      "decorators": [],
      "span": {
        "start": 19,
        "end": 60,
        "ctxt": 0
      },
      "body": null,
      "generator": false,
      "async": false,
      "typeParameters": null,
      "returnType": {
        "type": "TsTypeAnnotation",
        "span": {
          "start": 39,
          "end": 59,
          "ctxt": 0
        },
        "typeAnnotation": {
          "type": "TsUnionType",
          "span": {
            "start": 41,
            "end": 59,
            "ctxt": 0
          },
          "types": [
            {
              "type": "TsKeywordType",
              "span": {
                "start": 41,
                "end": 47,
                "ctxt": 0
              },
              "kind": "string"
            },
            {
              "type": "TsKeywordType",
              "span": {
                "start": 50,
                "end": 59,
                "ctxt": 0
              },
              "kind": "undefined"
            }
          ]
        }
      }
    },
    {
      "type": "VariableDeclaration",
      "span": {
        "start": 62,
        "end": 83,
        "ctxt": 0
      },
      "kind": "let",
      "declare": false,
      "declarations": [
        {
          "type": "VariableDeclarator",
          "span": {
            "start": 66,
            "end": 83,
            "ctxt": 0
          },
          "id": {
            "type": "Identifier",
            "span": {
              "start": 66,
              "end": 68,
              "ctxt": 0
            },
            "value": "gg",
            "optional": false,
            "typeAnnotation": null
          },
          "init": {
            "type": "BinaryExpression",
            "span": {
              "start": 71,
              "end": 83,
              "ctxt": 0
            },
            "operator": "??",
            "left": {
              "type": "CallExpression",
              "span": {
                "start": 71,
                "end": 74,
                "ctxt": 0
              },
              "callee": {
                "type": "Identifier",
                "span": {
                  "start": 71,
                  "end": 72,
                  "ctxt": 0
                },
                "value": "f",
                "optional": false
              },
              "arguments": [],
              "typeArguments": null
            },
            "right": {
              "type": "StringLiteral",
              "span": {
                "start": 78,
                "end": 83,
                "ctxt": 0
              },
              "value": "foo",
              "raw": "'foo'"
            }
          },
          "definite": false
        }
      ]
    }
  ],
  "interpreter": null
}