How can I correctly mock opensearch indices.exist with jest

Question

I am using OpenSearch client and I would like to test the indices.exists, however when I run jest test, I get the error openSearchClient.indices.exists is not a function. How can I access the exists property using jest? I understand the below code is trying to access mockOpenSearchClient.indices().exists() but I've looked at the documentation but can't seem to figure out how to make it mock mockOpenSearchClient.indices.exists(), below is my mock setup

const mockOpenSearchClient = {
indices: jest.fn().mockImplementation(() => {
      return {
        exists: jest.fn((obj, cb) => {
          return cb("", existsResp);
        }),
      };
    }),
} as unknown as Client;

After following the jest documentation and example here I was able to modify my setup to the below code but still no success,

const mockOpenSearchClient = {
    indices: jest.fn().mockImplementation(() => {
      return {
        exists: jest.fn().mockImplementation(() => {
          return {
            statusCode: 200,
            body: true,
          };
        }),
      };
    }),
  } as unknown as Client;

If I log mockOpenSearchClient this is what I get back

openSearchClient {
      indices: [Function: mockConstructor] {
        _isMockFunction: true,
        getMockImplementation: [Function (anonymous)],
        mock: [Getter/Setter],
        mockClear: [Function (anonymous)],
        mockReset: [Function (anonymous)],
        mockRestore: [Function (anonymous)],
        mockReturnValueOnce: [Function (anonymous)],
        mockResolvedValueOnce: [Function (anonymous)],
        mockRejectedValueOnce: [Function (anonymous)],
        mockReturnValue: [Function (anonymous)],
        mockResolvedValue: [Function (anonymous)],
        mockRejectedValue: [Function (anonymous)],
        mockImplementationOnce: [Function (anonymous)],
        withImplementation: [Function: bound withImplementation],
        mockImplementation: [Function (anonymous)],
        mockReturnThis: [Function (anonymous)],
        mockName: [Function (anonymous)],
        getMockName: [Function (anonymous)]
      }
    }

How do I successfully access the mockOpenSearchClient.indices.exists method?

Answer 1

So I was finally able to mock it by simply constructing an object and then mocking the resolved value to the function:

const mockOpenSearchClient = {
   indices: {
     exists: jest.fn().mockResolvedValue(existsResp);
     get: jest.fn().mockResolvedValue(getResp);
   }
} as unknown as Client;