internalPlugin.ts

import type { BaseContext, ApolloServerPlugin } from './externalTypes/index.js';

// This file's exports should not be exported from the overall
// @apollo/server module.

// The internal plugins implement this interface which
// ApolloServer.ensurePluginInstantiation uses to figure out if the plugins have
// already been installed (or explicitly disabled via the matching Disable
// plugins).
export interface InternalApolloServerPlugin<TContext extends BaseContext>
  extends ApolloServerPlugin<TContext> {
  // Used to identify a few specific plugins that are instantiated
  // by default if not explicitly used or disabled.
  __internal_plugin_id__(): InternalPluginId;
}

// Helper function for writing internal plugins which lets you write an object
// that is type-checked as InternalApolloServerPlugin but is still only of type
// ApolloServerPlugin (as appropriate for externally-exported plugin-returning
// functions).
export function internalPlugin<TContext extends BaseContext>(
  p: InternalApolloServerPlugin<TContext>,
): ApolloServerPlugin<TContext> {
  return p;
}

export type InternalPluginId =
  | 'CacheControl'
  | 'LandingPageDisabled'
  | 'SchemaReporting'
  | 'InlineTrace'
  | 'UsageReporting';

export function pluginIsInternal<TContext extends BaseContext>(
  plugin: ApolloServerPlugin<TContext>,
): plugin is InternalApolloServerPlugin<TContext> {
  // We could call the function and compare it to the list above, but this seems
  // good enough.
  return '__internal_plugin_id__' in plugin;
}