Why is toJSON required for generateKeywordIdeas?

[amosbastian]

I am trying to generate keyword ideas with

const result = await customer.keywordPlanIdeas.generateKeywordIdeas({
  customer_id: Config.GOOGLE_CUSTOMER_ID,
  geo_target_constants: [],
  include_adult_keywords: true,
  keyword_plan_network: "UNSPECIFIED",
  keyword_annotation: [],
  page_size: 10,
  page_token: "",
  ...request,
});

but it's complaining that

Types of property 'toJSON' are incompatible.
    Type '(() => { [k: string]: any; }) | undefined' is not assignable to type '() => { [k: string]: any; }'.

Of course you can just add

toJSON: () => ({}),

but then again, why is it required? And what does it actually do? There isn't any documentation for it as far as I can tell.

[lalawow]

The args of customer.keywordPlanIdeas.generateKeywordIdeas is a class.
So we'd better to use these rpcs in this way:

    const request = new services.GenerateKeywordIdeasRequest({
      customer_id: GOOGLE_ADS_CUSTOMER_ID,
      geo_target_constants: [],
      include_adult_keywords: true,
      keyword_plan_network: 'UNSPECIFIED',
      keyword_annotation: [],
      page_size: 10,
      page_token: '',
      ...options,
    });

    const result =
      await customer.keywordPlanIdeas.generateKeywordIdeas(request);

[lalawow]

BTW, these classes are defined in google-ads-node.