feat(graphql): query verifies the response

[2ndalpha]

Breaking change how Qminder.GraphQL.query works.

• It does not take string as an argument. Have to use gql from graphql-tag
• It throws when there is no data in the response
• It returns data from unwrapped response
• It supports generics

Example usage is in app.ts

[KarlMae]

While testing I converted some services to use the generic and it's so much cleaner, thanks!

I left some improvement ideas.

[KarlMae]

IMO the function would read much smoother like this:

    let response = await fetch(`https://${this.apiServer}/graphql`, init);
    let responseJson = await response.json();

    if (responseJson.errors?.length) {
      throw this.extractGraphQLError(responseJson);
    }
    
    if (!responseJson.data) {
      throw new Error(`Server response is not valid GraphQL response. Response: ${ JSON.stringify(responseJson) }`);
    }
    
    return responseJson.data as T;

It subjectively has an easier to follow structure:

1. Fetch
2. Check for errors
3. Check for data and unwrap it

---

The casting is also not necessary?

let graphQLResponse: GraphqlResponse = responseJson;

[2ndalpha]

Casting is still needed but I refactored it a bit

[KarlMae]

I think we can remove this check as well.

Query can not be undefined as it is clearly set on the line above.
Query can also not have length 0 because gql DocumentNode can not be empty as tested here:

DOM

<button (click)="handleClick()">Test</button>

class

async handleClick(): Promise<void> {
    await Qminder.GraphQL.query(gql``); 
  }

Result

Screen.Recording.2025-01-06.at.10.31.25.mov

[KarlMae]

Let's go 🚀