# old/mod.ts
export class Dict {
  [key: string]: number;
}

# new/mod.ts
export class Dict {
  [key: string]: string;
}

# output.json
{
  "modifiedModules": {
    "file:///mod.ts": {
      "modified": [
        {
          "name": "Dict",
          "declarations": {
            "modified": [
              {
                "kind": "class",
                "defChanges": {
                  "type": "class",
                  "indexSignatureChanges": {
                    "modified": [
                      {
                        "index": 0,
                        "typeChange": {
                          "old": {
                            "repr": "number",
                            "kind": "keyword",
                            "value": "number"
                          },
                          "new": {
                            "repr": "string",
                            "kind": "keyword",
                            "value": "string"
                          }
                        }
                      }
                    ]
                  }
                }
              }
            ]
          }
        }
      ]
    }
  }
}
