From a9a32a48dbe652c9e9b008159d0409148220aefb Mon Sep 17 00:00:00 2001
From: Julien Ripouteau <julien@ripouteau.com>
Date: Tue, 9 Apr 2024 02:20:56 +0200
Subject: [PATCH] feat: import.meta.hot.dump function

---
 packages/hot_hook/src/dependency_tree.ts | 16 ++++++++++++++++
 packages/hot_hook/src/hot.ts             | 23 +++++++++++++++++++----
 packages/hot_hook/src/loader.ts          | 20 +++++++++++++++++---
 3 files changed, 52 insertions(+), 7 deletions(-)

diff --git a/packages/hot_hook/src/dependency_tree.ts b/packages/hot_hook/src/dependency_tree.ts
index 895d0f2..79eabc9 100644
--- a/packages/hot_hook/src/dependency_tree.ts
+++ b/packages/hot_hook/src/dependency_tree.ts
@@ -1,3 +1,5 @@
+import { dirname, relative } from 'node:path'
+
 /**
  * Represent a file node in the dependency tree.
  */
@@ -179,4 +181,18 @@ export default class DependencyTree {
     const result = checkPathToRoot(node)
     return result
   }
+
+  dump() {
+    const rootDirname = dirname(this.#tree.path)
+    const isNodeModule = (path: string) => path.includes('node_modules')
+
+    return Array.from(this.#pathMap.values()).map((node) => ({
+      path: relative(rootDirname, node.path),
+      boundary: node.reloadable,
+      reloadable: isNodeModule(node.path) ? false : this.isReloadable(node.path),
+      version: node.version,
+      dependencies: Array.from(node.dependencies).map((n) => relative(rootDirname, n.path)),
+      dependents: Array.from(node.dependents).map((n) => relative(rootDirname, n.path)),
+    }))
+  }
 }
diff --git a/packages/hot_hook/src/hot.ts b/packages/hot_hook/src/hot.ts
index bcbaa32..b0b11b8 100644
--- a/packages/hot_hook/src/hot.ts
+++ b/packages/hot_hook/src/hot.ts
@@ -1,8 +1,11 @@
 import { register } from 'node:module'
+import { MessageChannel } from 'node:worker_threads'
+
 import { InitOptions, InitializeHookOptions, MessageChannelMessage } from './types.js'
 
 class Hot {
   #options!: InitOptions
+  #messageChannel!: MessageChannel
   #declinePaths = new Set<string>()
   #disposeCallbacks = new Map<string, () => void>()
 
@@ -49,20 +52,20 @@ class Hot {
      * between the hook and the application process since hooks
      * are running in a worker thread
      */
-    const { port1, port2 } = new MessageChannel()
+    this.#messageChannel = new MessageChannel()
 
     register('hot-hook/loader', {
       parentURL: import.meta.url,
-      transferList: [port2],
+      transferList: [this.#messageChannel.port2],
       data: {
-        messagePort: port2,
+        messagePort: this.#messageChannel.port2,
         root: this.#options.root,
         ignore: this.#options.ignore,
         boundaries: this.#options.boundaries,
       } satisfies InitializeHookOptions,
     })
 
-    port1.on('message', this.#onMessage.bind(this))
+    this.#messageChannel.port1.on('message', this.#onMessage.bind(this))
   }
 
   /**
@@ -83,6 +86,18 @@ class Hot {
   decline(url: string) {
     this.#declinePaths.add(new URL(url).pathname)
   }
+
+  /**
+   * Dump the current state hot hook
+   */
+  async dump() {
+    this.#messageChannel.port1.postMessage({ type: 'hot-hook:dump' })
+    const result = await new Promise((resolve) =>
+      this.#messageChannel.port1.once('message', (message) => resolve(message))
+    )
+
+    return result
+  }
 }
 
 // @ts-ignore
diff --git a/packages/hot_hook/src/loader.ts b/packages/hot_hook/src/loader.ts
index 5b321b0..3eae7a5 100644
--- a/packages/hot_hook/src/loader.ts
+++ b/packages/hot_hook/src/loader.ts
@@ -26,9 +26,18 @@ export class HotHookLoader {
     this.#pathIgnoredMatcher = new Matcher(this.#projectRoot, options.ignore)
     this.#hardcodedBoundaryMatcher = new Matcher(this.#projectRoot, options.boundaries)
 
-    this.#dependencyTree = new DependencyTree({
-      root: options.root,
-    })
+    this.#dependencyTree = new DependencyTree({ root: options.root })
+    this.#messagePort?.on('message', (message) => this.#onMessage(message))
+  }
+
+  /**
+   * When a message is received from the main thread
+   */
+  #onMessage(message: any) {
+    if (message.type !== 'hot-hook:dump') return 
+
+    const dump = this.#dependencyTree.dump()
+    this.#messagePort?.postMessage({ type: 'hot-hook:dump', dump })
   }
 
   /**
@@ -89,6 +98,11 @@ export class HotHookLoader {
       hot.decline(import.meta.url);
     };
 
+    import.meta.hot.dump = async () => {
+      const { hot } = await import('hot-hook');
+      return hot.dump();
+    };
+
     import.meta.hot.boundary = { with: { hot: 'true' } };
     `