graphql-modules/esm/application/subscription.js

Create reusable, maintainable, testable and extendable GraphQL modules

import { subscribe, } from 'graphql';
import { tapAsyncIterator, isAsyncIterable, isNotSchema, } from '../shared/utils';
export function subscriptionCreator({ contextBuilder, }) {
    const createSubscription = (options) => {
        // Custom or original subscribe function
        const subscribeFn = (options === null || options === void 0 ? void 0 : options.subscribe) || subscribe;
        return (argsOrSchema, document, rootValue, contextValue, variableValues, operationName, fieldResolver, subscribeFieldResolver) => {
            function perform({ context, ɵdestroy: destroy, }) {
                const subscriptionArgs = isNotSchema(argsOrSchema)
                    ? {
                        ...argsOrSchema,
                        contextValue: context,
                    }
                    : {
                        schema: argsOrSchema,
                        document: document,
                        rootValue,
                        contextValue: context,
                        variableValues,
                        operationName,
                        fieldResolver,
                        subscribeFieldResolver,
                    };
                let isIterable = false;
                // It's important to wrap the subscribeFn within a promise
                // so we can easily control the end of subscription (with finally)
                return Promise.resolve()
                    .then(() => subscribeFn(subscriptionArgs))
                    .then((sub) => {
                    if (isAsyncIterable(sub)) {
                        isIterable = true;
                        return tapAsyncIterator(sub, destroy);
                    }
                    return sub;
                })
                    .finally(() => {
                    if (!isIterable) {
                        destroy();
                    }
                });
            }
            if (options === null || options === void 0 ? void 0 : options.controller) {
                return perform(options.controller);
            }
            return contextBuilder(isNotSchema(argsOrSchema)
                ? argsOrSchema.contextValue
                : contextValue).runWithContext(perform);
        };
    };
    return createSubscription;
}