{
  "type": "Program",
  "statements": [
    {
      "type": "TSInterfaceDeclaration",
      "body": {
        "type": "TSInterfaceBody",
        "body": [
          {
            "type": "TSPropertySignature",
            "computed": false,
            "optional": false,
            "readonly": false,
            "key": {
              "type": "Identifier",
              "name": "a",
              "loc": {
                "start": {
                  "line": 18,
                  "column": 5
                },
                "end": {
                  "line": 18,
                  "column": 6
                }
              }
            },
            "typeAnnotation": {
              "type": "TSUnionType",
              "types": [
                {
                  "type": "TSStringKeyword",
                  "loc": {
                    "start": {
                      "line": 18,
                      "column": 8
                    },
                    "end": {
                      "line": 18,
                      "column": 14
                    }
                  }
                },
                {
                  "type": "TSUndefinedKeyword",
                  "loc": {
                    "start": {
                      "line": 19,
                      "column": 7
                    },
                    "end": {
                      "line": 19,
                      "column": 16
                    }
                  }
                }
              ],
              "loc": {
                "start": {
                  "line": 18,
                  "column": 8
                },
                "end": {
                  "line": 19,
                  "column": 16
                }
              }
            },
            "loc": {
              "start": {
                "line": 18,
                "column": 5
              },
              "end": {
                "line": 19,
                "column": 17
              }
            }
          }
        ],
        "loc": {
          "start": {
            "line": 17,
            "column": 13
          },
          "end": {
            "line": 20,
            "column": 2
          }
        }
      },
      "id": {
        "type": "Identifier",
        "name": "B",
        "loc": {
          "start": {
            "line": 17,
            "column": 11
          },
          "end": {
            "line": 17,
            "column": 12
          }
        }
      },
      "extends": [],
      "loc": {
        "start": {
          "line": 17,
          "column": 1
        },
        "end": {
          "line": 20,
          "column": 2
        }
      }
    }
  ],
  "loc": {
    "start": {
      "line": 1,
      "column": 1
    },
    "end": {
      "line": 20,
      "column": 2
    }
  }
}
