`mutate` function leaves `data` and `variables` un-typed.

Intended outcome: apollo-client uses strong typing. This issue is specifically addressing mutate’s variables and data.

Actual outcome: The results of mutate are untyped, as are the variables in the options.

How to reproduce the issue: While this issue covers multiple projects’ types, the problem is exposed by usage of apollo-client mutate.

apollo-client.mutate is virtually un-typed (e.g. data and variables in typescript). The types that need parameterized adjustments cross apollo-client, apollo-link, and graphql projects. Specifically the data result and variables are unsealed/unchecked and need to be cast if the user wants to use them after fetching.

• apollo-client mutate:

mutate<T>(options: MutationOptions<T>): Promise<FetchResult<T>>

• apollo-link FetchResult:

export declare type FetchResult<C = Record<string, any>, E = Record<string, any>> = ExecutionResult & {
    extensions?: E;
    context?: C;
};

• graphql ExecutionResult:

export interface ExecutionResult {
    data?: { [key: string]: any };
    extensions?: { [key: string]: any };
    errors?: GraphQLError[];
}

Summary

1. data - The mutate<T> from apollo-client doesn’t type the result, it types FetchResult<T> position 1, which is the context. The result is in ExecutionResult which is entirely unsealed/untyped data?: { [key: string]: any }
2. variables - MutationOptions<T> doesn’t allow for typing of variables - they are explicitly any

export interface MutationBaseOptions<T = {
    [key: string]: any;
}> {
    optimisticResponse?: Object | Function;
    updateQueries?: MutationQueryReducersMap<T>;
    refetchQueries?: ((result: ExecutionResult) => RefetchQueryDescription) | RefetchQueryDescription;
    update?: MutationUpdaterFn<T>;
    errorPolicy?: ErrorPolicy;
    variables?: any;
}
export interface MutationOptions<T = {
    [key: string]: any;
}> extends MutationBaseOptions<T> {
    mutation: DocumentNode;
    context?: any;
}

1. I suggest any parameterized type named T be renamed for clarity to expose issues such as this.

Version

• apollo-client@2.0.4

[rosskevin]

I have tested the PR locally via augmentation with:

// https://github.com/apollographql/apollo-link/pull/804
// https://github.com/apollographql/apollo-client/issues/2795#issuecomment-424124181

import { ExecutionResult } from 'graphql'

declare module 'apollo-link' {
  export type FetchResult<
    TData = { [key: string]: any },
    C = Record<string, any>,
    E = Record<string, any>
  > = ExecutionResult<TData> & {
    extensions?: E
    context?: C
  }
}

It seems to be working out of the box since apollo-client was trying to pass through the the TData as position 1, albeit errantly as it was applied to C. By adding the above in the PR, it-just-works. Hopefully the apollo-link PR is merged/released.

[alexbjorlig]

Our team is having issues with this bug, no typings on mutation. We are using apollo-link 1.2.11. Created a stackblitz to illustrate the issue: https://stackblitz.com/edit/apollo-no-typings-on-mutation

@rosskevin are we not expecting typings to work here?