add file watching to JS API (FredKSchott#1452)

peterhpchen · Oct 31, 2020 · 3411a53 · 3411a53
1 parent ea3f05f
commit 3411a53
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diff --git a/snowpack/src/commands/dev.ts b/snowpack/src/commands/dev.ts
@@ -68,6 +68,7 @@ import {
   SnowpackBuildMap,
   LoadResult,
   SnowpackDevServer,
+  OnFileChangeCallback,
 } from '../types/snowpack';
 import {
   BUILD_CACHE,
@@ -1335,9 +1336,13 @@ export async function startDevServer(commandOptions: CommandOptions): Promise<Sn
   // Defer "chokidar" loading to here, to reduce impact on overall startup time
   const chokidar = await import('chokidar');
 
+  // Allow the user to hook into this callback, if they like (noop by default)
+  let onFileChangeCallback: OnFileChangeCallback = () => {};
+
   // Watch src files
   async function onWatchEvent(fileLoc: string) {
     logger.info(colors.cyan('File changed...'));
+    onFileChangeCallback({filePath: fileLoc});
     const updatedUrl = getUrlForFile(fileLoc, config);
     if (updatedUrl) {
       handleHmrUpdate(fileLoc, updatedUrl);
@@ -1407,6 +1412,7 @@ export async function startDevServer(commandOptions: CommandOptions): Promise<Sn
     handleRequest,
     sendResponseFile,
     sendResponseError,
+    onFileChange: (callback) => (onFileChangeCallback = callback),
     async shutdown() {
       await watcher.close();
       server.close();

diff --git a/snowpack/src/types/snowpack.ts b/snowpack/src/types/snowpack.ts
@@ -18,6 +18,7 @@ export interface LoadResult<T = Buffer | string> {
   checkStale?: () => Promise<void>;
 }
 
+export type OnFileChangeCallback = ({filePath: string}) => any;
 export interface SnowpackDevServer {
   port: number;
   loadUrl: {
@@ -59,6 +60,7 @@ export interface SnowpackDevServer {
     {contents, originalFileLoc, responseFileName}: LoadResult,
   ) => void;
   sendResponseError: (req: http.IncomingMessage, res: http.ServerResponse, status: number) => void;
+  onFileChange: (callback: OnFileChangeCallback) => void;
   shutdown(): Promise<void>;
 }