fix(internal): Improve loader by adding a merged loader and incorpora…

…ting `SchemaOrigin` parsing (#165)

.changeset/twelve-tips-rush.md

@@ -0,0 +1,6 @@
+---
+"@gql.tada/cli-utils": patch
+"@gql.tada/internal": patch
+---
+
+Update internal loader to merge them into one and incorporate `SchemaOrigin` parsing

packages/cli-utils/src/index.ts

@@ -6,10 +6,10 @@ import { printSchema } from 'graphql';
 
 import type { GraphQLSchema } from 'graphql';
 import type { TsConfigJson } from 'type-fest';
-import { resolveTypeScriptRootDir } from '@gql.tada/internal';
+import { resolveTypeScriptRootDir, load } from '@gql.tada/internal';
 
 import { getGraphQLSPConfig } from './lsp';
-import { ensureTadaIntrospection, makeLoader } from './tada';
+import { ensureTadaIntrospection } from './tada';
 
 interface GenerateSchemaOptions {
   headers?: Record<string, string>;
@@ -21,7 +21,8 @@ export async function generateSchema(
   target: string,
   { headers, output, cwd = process.cwd() }: GenerateSchemaOptions
 ) {
-  const loader = makeLoader(cwd, headers ? { url: target, headers } : target);
+  const origin = headers ? { url: target, headers } : target;
+  const loader = load({ origin, rootPath: cwd });
 
   let schema: GraphQLSchema | null;
   try {

packages/cli-utils/src/lsp.ts

@@ -1,11 +1,5 @@
 import type { TsConfigJson } from 'type-fest';
-
-export type SchemaOrigin =
-  | string
-  | {
-      url: string;
-      headers: HeadersInit;
-    };
+import type { SchemaOrigin } from '@gql.tada/internal';
 
 export type GraphQLSPConfig = {
   name: string;

packages/cli-utils/src/tada.ts

@@ -1,17 +1,14 @@
 import { promises as fs } from 'node:fs';
 import path from 'node:path';
 import type { IntrospectionQuery } from 'graphql';
-import type { SchemaLoader } from '@gql.tada/internal';
 
 import {
+  type SchemaOrigin,
   minifyIntrospection,
   outputIntrospectionFile,
-  loadFromSDL,
-  loadFromURL,
+  load,
 } from '@gql.tada/internal';
 
-import type { SchemaOrigin } from './lsp';
-
 /**
  * This function mimics the behavior of the LSP, this so we can ensure
  * that gql.tada will work in any environment. The JetBrains IDE's do not
@@ -20,12 +17,12 @@ import type { SchemaOrigin } from './lsp';
  * this function.
  */
 export async function ensureTadaIntrospection(
-  schemaLocation: SchemaOrigin,
+  origin: SchemaOrigin,
   outputLocation: string,
   base: string = process.cwd(),
   shouldPreprocess = true
 ) {
-  const loader = makeLoader(base, schemaLocation);
+  const loader = load({ origin, rootPath: base });
 
   let introspection: IntrospectionQuery | null;
   try {
@@ -52,36 +49,3 @@ export async function ensureTadaIntrospection(
     console.error('Something went wrong while writing the introspection file', error);
   }
 }
-
-const getURLConfig = (origin: SchemaOrigin) => {
-  if (typeof origin === 'string') {
-    try {
-      return { url: new URL(origin) };
-    } catch (_error) {
-      return null;
-    }
-  } else if (typeof origin.url === 'string') {
-    try {
-      return {
-        url: new URL(origin.url),
-        headers: origin.headers,
-      };
-    } catch (error) {
-      throw new Error(`Input URL "${origin.url}" is invalid`);
-    }
-  } else {
-    return null;
-  }
-};
-
-export function makeLoader(root: string, origin: SchemaOrigin): SchemaLoader {
-  const urlOrigin = getURLConfig(origin);
-  if (urlOrigin) {
-    return loadFromURL(urlOrigin);
-  } else if (typeof origin === 'string') {
-    const file = path.resolve(root, origin);
-    return loadFromSDL({ file, assumeValid: true });
-  } else {
-    throw new Error(`Configuration contains an invalid "schema" option`);
-  }
-}

packages/internal/src/loaders/index.ts

@@ -1,3 +1,41 @@
-export type { SchemaLoader } from './types';
-export { loadFromSDL } from './sdl';
-export { loadFromURL } from './url';
+export type * from './types';
+
+import path from 'node:path';
+import type { SchemaLoader, SchemaOrigin } from './types';
+import { loadFromSDL } from './sdl';
+import { loadFromURL } from './url';
+
+export { loadFromSDL, loadFromURL };
+
+const getURLConfig = (origin: SchemaOrigin | null) => {
+  try {
+    return (
+      origin && {
+        url: new URL(typeof origin === 'object' ? origin.url : origin),
+        headers: typeof origin === 'object' ? origin.headers : undefined,
+      }
+    );
+  } catch (_error) {
+    throw new Error(`Configuration contains an invalid "schema" option`);
+  }
+};
+
+export interface LoadConfig {
+  origin: SchemaOrigin;
+  rootPath?: string;
+  fetchInterval?: number;
+  assumeValid?: boolean;
+}
+
+export function load(config: LoadConfig): SchemaLoader {
+  const urlOrigin = getURLConfig(origin);
+  if (urlOrigin) {
+    return loadFromURL({ ...urlOrigin, interval: config.fetchInterval });
+  } else if (typeof origin === 'string') {
+    const file = config.rootPath ? path.resolve(config.rootPath, origin) : origin;
+    const assumeValid = config.assumeValid != null ? config.assumeValid : true;
+    return loadFromSDL({ file, assumeValid });
+  } else {
+    throw new Error(`Configuration contains an invalid "schema" option`);
+  }
+}

packages/internal/src/loaders/sdl.ts

@@ -1,13 +1,13 @@
-import type { IntrospectionQuery, GraphQLSchema } from 'graphql';
+import type { IntrospectionQuery } from 'graphql';
 import { buildSchema, buildClientSchema, executeSync } from 'graphql';
 import { CombinedError } from '@urql/core';
 import fs from 'node:fs/promises';
 import path from 'node:path';
 
-import type { SupportedFeatures } from './query';
 import { makeIntrospectionQuery } from './query';
+import type { SupportedFeatures } from './query';
 
-import type { SchemaLoader } from './types';
+import type { SchemaLoader, SchemaLoaderResult, OnSchemaUpdate } from './types';
 
 interface LoadFromSDLConfig {
   assumeValid?: boolean;
@@ -21,68 +21,62 @@ const ALL_SUPPORTED_FEATURES: SupportedFeatures = {
 };
 
 export function loadFromSDL(config: LoadFromSDLConfig): SchemaLoader {
-  const subscriptions = new Set<() => void>();
+  const subscriptions = new Set<OnSchemaUpdate>();
 
   let controller: AbortController | null = null;
-  let introspection: IntrospectionQuery | null = null;
-  let schema: GraphQLSchema | null = null;
+  let result: SchemaLoaderResult | null = null;
+
+  const load = async (): Promise<typeof result> => {
+    const ext = path.extname(config.file);
+    const data = await fs.readFile(config.file, { encoding: 'utf8' });
+    if (ext === '.json') {
+      let introspection: IntrospectionQuery | null = null;
+      try {
+        introspection = JSON.parse(data);
+      } catch (_error) {}
+      return (
+        introspection && {
+          introspection,
+          schema: buildClientSchema(introspection, { assumeValid: !!config.assumeValid }),
+        }
+      );
+    } else {
+      const schema = buildSchema(data, { assumeValidSDL: !!config.assumeValid });
+      const query = makeIntrospectionQuery(ALL_SUPPORTED_FEATURES);
+      const queryResult = executeSync({ schema, document: query });
+      if (queryResult.errors) {
+        throw new CombinedError({ graphQLErrors: queryResult.errors as any[] });
+      } else if (queryResult.data) {
+        const introspection = queryResult.data as unknown as IntrospectionQuery;
+        return { introspection, schema };
+      } else {
+        return null;
+      }
+    }
+  };
 
   const watch = async () => {
     controller = new AbortController();
     const watcher = fs.watch(config.file, {
-      persistent: false,
       signal: controller.signal,
+      persistent: false,
     });
-
     try {
-      for await (const event of watcher) {
-        if (event.eventType === 'rename' || !subscriptions.size) break;
-        for (const subscriber of subscriptions) subscriber();
+      for await (const _event of watcher) {
+        if ((result = await load())) {
+          for (const subscriber of subscriptions) subscriber(result);
+        }
       }
     } catch (error: any) {
-      if (error.name === 'AbortError') {
-        return;
-      } else {
-        throw error;
-      }
+      if (error.name !== 'AbortError') throw error;
     } finally {
       controller = null;
     }
   };
 
-  const introspect = async () => {
-    const ext = path.extname(config.file);
-    const data = await fs.readFile(config.file, { encoding: 'utf8' });
-    if (ext === '.json') {
-      introspection = JSON.parse(data) || null;
-      schema =
-        introspection && buildClientSchema(introspection, { assumeValid: !!config.assumeValid });
-      return introspection;
-    } else {
-      schema = buildSchema(data, { assumeValidSDL: !!config.assumeValid });
-      const query = makeIntrospectionQuery(ALL_SUPPORTED_FEATURES);
-      const result = executeSync({ schema, document: query });
-      if (result.errors) {
-        throw new CombinedError({ graphQLErrors: result.errors as any[] });
-      } else if (result.data) {
-        return (introspection = (result.data as any) || null);
-      } else {
-        return (introspection = null);
-      }
-    }
-  };
-
   return {
-    async loadIntrospection() {
-      return introspect();
-    },
-    async loadSchema() {
-      if (schema) {
-        return schema;
-      } else {
-        await this.loadIntrospection();
-        return schema;
-      }
+    async load(reload?: boolean) {
+      return reload || !result ? (result = await load()) : result;
     },
     notifyOnUpdate(onUpdate) {
       if (!subscriptions.size) watch();
@@ -94,5 +88,13 @@ export function loadFromSDL(config: LoadFromSDLConfig): SchemaLoader {
         }
       };
     },
+    async loadIntrospection() {
+      const result = await this.load();
+      return result && result.introspection;
+    },
+    async loadSchema() {
+      const result = await this.load();
+      return result && result.schema;
+    },
   };
 }

packages/internal/src/loaders/types.ts

@@ -1,7 +1,25 @@
 import type { IntrospectionQuery, GraphQLSchema } from 'graphql';
 
+export interface SchemaLoaderResult {
+  introspection: IntrospectionQuery;
+  schema: GraphQLSchema;
+}
+
+export type OnSchemaUpdate = (result: SchemaLoaderResult) => void;
+
 export interface SchemaLoader {
+  load(reload?: boolean): Promise<SchemaLoaderResult | null>;
+  notifyOnUpdate(onUpdate: OnSchemaUpdate): () => void;
+
+  /** @internal */
   loadIntrospection(): Promise<IntrospectionQuery | null>;
+  /** @internal */
   loadSchema(): Promise<GraphQLSchema | null>;
-  notifyOnUpdate(onUpdate: () => void): () => void;
 }
+
+export type SchemaOrigin =
+  | string
+  | {
+      url: string;
+      headers?: HeadersInit;
+    };