Add watch polling configuration (#4823)

* Add watch polling configuration

- Change usePolling default from `true` to `false`
- add `watchPolling` config file option to configure polling

* Update watch config structure

* Include changeset message

.changeset/funny-bikes-switch.md

@@ -0,0 +1,5 @@
+---
+'@graphql-codegen/cli': minor
+---
+
+Changes watch mode to not use polling by default and adds configurable override

packages/graphql-codegen-cli/src/utils/watcher.ts

@@ -24,7 +24,7 @@ function emitWatching() {
 export const createWatcher = (
   initalContext: CodegenContext,
   onNext: (result: Types.FileOutput[]) => Promise<Types.FileOutput[]>
-) => {
+): Promise<void> => {
   debugLog(`[Watcher] Starting watcher...`);
   let config: Types.Config & { configFilePath?: string } = initalContext.getConfig();
   const files: string[] = [initalContext.filepath].filter(a => a);
@@ -94,9 +94,8 @@ export const createWatcher = (
       followSymlinks: true,
       cwd: process.cwd(),
       disableGlobbing: false,
-      usePolling: true,
-      interval: 100,
-      binaryInterval: 300,
+      usePolling: config.watchConfig?.usePolling,
+      interval: config.watchConfig?.interval,
       depth: 99,
       awaitWriteFinish: true,
       ignorePermissionErrors: false,
@@ -141,7 +140,7 @@ export const createWatcher = (
   };
 
   // the promise never resolves to keep process running
-  return new Promise((resolve, reject) => {
+  return new Promise<void>((resolve, reject) => {
     executeCodegen(initalContext)
       .then(onNext, () => Promise.resolve())
       .then(runWatcher)

packages/utils/plugins-helpers/src/types.ts

@@ -414,6 +414,17 @@ export namespace Types {
      * For more details: https://graphql-code-generator.com/docs/getting-started/development-workflow#watch-mode
      */
     watch?: boolean | string | string[];
+    /**
+     * @description Allows overriding the behavior of watch to use stat polling over native file watching support.
+     *
+     * Config fields have the same defaults and sematics as the identically named ones for chokidar.
+     *
+     * For more details: https://graphql-code-generator.com/docs/getting-started/development-workflow#watch-mode
+     */
+    watchConfig?: {
+      usePolling: boolean;
+      interval?: number;
+    };
     /**
      * @description A flag to suppress printing errors when they occur.
      */

website/docs/getting-started/development-workflow.md

@@ -50,6 +50,17 @@ If you wish, you can specify a custom list of files to watch, by adding a glob e
 Use this when you are loading your schema or documents from a single code file, that depends on other files internally, because codegen can't tell that you using those files automatically.   
 :::
 
+By default, watch mode uses the system's native support to listen for file change events. This can be configured in the settings file to use a stat polling method instead in unusual cases where system support is unavailable.
+
+```yml
+watch: true
+# Passed directly through to chokidar's file watch configuration
+watchConfig: 
+  usePolling: true
+  interval: 1000
+```
+
+
 ### Monorepo and Yarn Workspaces
 
 If you are using a monorepo structure, with tools such as [Yarn Workspaces](https://yarnpkg.com/lang/en/docs/workspaces/) or [Lerna](https://github.com/lerna/lerna), we recommend to install the codegen in the root of your monorepo.