My custom graphql apollo client request helper

request.ts

import {DocumentNode} from "graphql";
import apollo from "@/grapthql/apollo"; // pre-configured apollo client (authorization...etc)

/**
 * contains apollo request helpers
 */
const request = {
    /**
     * send an apollo mutate request
     * @param mutation the gqlMutation definition
     * @param variables any variables required by the gqlMutation
     * @param onSuccess a function which will be chained on the promise .then() method,
     *  it is suggested that the onSuccess method returns the value back to allow other .then() promise-chain methods to consume the value
     * @template E the type of the expected result default is Boolean
     * @return promise, if the onSuccess function was passed and it didnt return the value back, then you can't consume the value on the next .then() promise-chain
     */
    mutate: function <E = boolean>(mutation: DocumentNode, variables?: {}, onSuccess?: (result: E) => void | E): Promise<E> {
        const promise = apollo.mutate<E[]>({
            mutation: mutation,
            variables: variables
        }).then(res => Object.values(res.data as E[])[0])
        if (onSuccess) {
            promise.then(onSuccess)
        }
        return promise
    },
    /**
     * send an apollo query request
     * @param query the gqlQuery definition
     * @param variables any variables required by the gqlQuery
     * @param onSuccess a function which will be chained on the promise .then() method,
     *  it is suggested that the onSuccess method returns the value back to allow other .then() promise-chain methods to consume the value
     * @template E the type of the expected result
     * @return promise, if the onSuccess function was passed and it didnt return the value back, then you can't consume the value on the next .then() promise-chain
     */
    query: function <E>(query: DocumentNode, variables?: {}, onSuccess?: (result: E) => void | E): Promise<E> {
        const promise = apollo.query<E[]>({
            query: query,
            variables: variables
        }).then(res => Object.values(res.data)[0])
        if (onSuccess) {
            promise.then(onSuccess)//
        }
        return promise
    }
}
export default request