graphile-build/node8plus/plugins/SubscriptionPlugin.js

Build a GraphQL schema from plugins

"use strict";

Object.defineProperty(exports, "__esModule", {
  value: true
});
exports.default = void 0;
function isValidSubscription(Subscription) {
  try {
    if (!Subscription) {
      return false;
    }
    if (Object.keys(Subscription.getFields()).length === 0) {
      return false;
    }
  } catch (e) {
    return false;
  }
  return true;
}
const description = `The root subscription type: contains realtime events you can subscribe to with the \`subscription\` operation.`;
const liveDescription = `The root subscription type: contains events and live queries you can subscribe to with the \`subscription\` operation.

#### Live Queries

Live query fields are differentiated by containing \`(live)\` at the end of their description, \
they are added for each field in the \`Query\` type. \
When you subscribe to a live query field, the selection set will be evaluated and sent to the \
client, and then most things\\* that would cause the output of the selection set to change \
will trigger the selection set to be re-evaluated and the results to be re-sent to the client.

_(\\* Not everything: typically only changes to persisted data referenced by the query are detected, not computed fields.)_

Live queries can be very expensive, so try and keep them small and focussed.

#### Events

Event fields will run their selection set when, and only when, the specified server-side event occurs. \
This makes them a lot more efficient than Live Queries, but it is still recommended that you keep payloads fairly small.`;
var SubscriptionPlugin = async function SubscriptionPlugin(builder, {
  live
}) {
  builder.hook("GraphQLSchema", (schema, build) => {
    const {
      newWithHooks,
      extend,
      graphql: {
        GraphQLObjectType
      },
      inflection
    } = build;
    const Subscription = newWithHooks(GraphQLObjectType, {
      name: inflection.builtin("Subscription"),
      description: build.wrapDescription(live ? liveDescription : description, "type")
    }, {
      __origin: `graphile-build built-in (root subscription type)`,
      isRootSubscription: true
    }, true);
    if (isValidSubscription(Subscription)) {
      return extend(schema, {
        subscription: Subscription
      }, "Adding subscription type to schema");
    } else {
      return schema;
    }
  }, ["Subscription"], [], ["Query"]);
};
exports.default = SubscriptionPlugin;
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