From c6e1a0b6fb9314186a46cf1352a8685e8aa5fe8d Mon Sep 17 00:00:00 2001
From: "(quasar) nebula" <qznebula@protonmail.com>
Date: Sat, 18 Mar 2023 20:15:37 -0300
Subject: data steps: experimental live JS reload infrastructure

---
 src/content/dependencies/index.js | 108 ++++++++++++++++++++++++++++++++++++++
 1 file changed, 108 insertions(+)
 create mode 100644 src/content/dependencies/index.js

(limited to 'src/content/dependencies/index.js')

diff --git a/src/content/dependencies/index.js b/src/content/dependencies/index.js
new file mode 100644
index 00000000..5cd116d4
--- /dev/null
+++ b/src/content/dependencies/index.js
@@ -0,0 +1,108 @@
+import chokidar from 'chokidar';
+import EventEmitter from 'events';
+import * as path from 'path';
+import {fileURLToPath} from 'url';
+
+import contentFunction from '../../content-function.js';
+import {color, logWarn} from '../../util/cli.js';
+import {annotateFunction} from '../../util/sugar.js';
+
+export function watchContentDependencies() {
+  const events = new EventEmitter();
+  const contentDependencies = {};
+
+  Object.assign(events, {
+    contentDependencies,
+  });
+
+  // Watch adjacent files
+  const metaPath = fileURLToPath(import.meta.url);
+  const metaDirname = path.dirname(metaPath);
+  const watcher = chokidar.watch(metaDirname);
+
+  watcher.on('all', (event, filePath) => {
+    if (!['add', 'change'].includes(event)) return;
+    if (filePath === metaPath) return;
+    handlePathUpdated(filePath);
+  });
+
+  watcher.on('unlink', (filePath) => {
+    if (filePath === metaPath) {
+      console.error(`Yeowzers content dependencies just got nuked.`);
+      return;
+    }
+    handlePathRemoved(filePath);
+  })
+
+  return events;
+
+  function getFunctionName(filePath) {
+    const shortPath = path.basename(filePath);
+    const functionName = shortPath.slice(0, -path.extname(shortPath).length);
+    return functionName;
+  }
+
+  async function handlePathRemoved(filePath) {
+    const functionName = getFunctionName(filePath);
+    delete contentDependencies[functionName];
+  }
+
+  async function handlePathUpdated(filePath) {
+    const functionName = getFunctionName(filePath);
+    let error = null;
+
+    main: {
+      let spec;
+      try {
+        spec = (await import(`${filePath}?${Date.now()}`)).default;
+      } catch (caughtError) {
+        error = caughtError;
+        error.message = `Error importing: ${error.message}`;
+        break main;
+      }
+
+      try {
+        if (typeof spec.data === 'function') {
+          annotateFunction(spec.data, {name: functionName, description: 'data'});
+        }
+
+        if (typeof spec.generate === 'function') {
+          annotateFunction(spec.generate, {name: functionName});
+        }
+      } catch (caughtError) {
+        error = caughtError;
+        error.message = `Error annotating functions: ${error.message}`;
+        break main;
+      }
+
+      let fn;
+      try {
+        fn = contentFunction(spec);
+      } catch (caughtError) {
+        error = caughtError;
+        error.message = `Error loading spec: ${error.message}`;
+        break main;
+      }
+
+      contentDependencies[functionName] = fn;
+    }
+
+    if (!error) {
+      return true;
+    }
+
+    if (contentDependencies[functionName]) {
+      logWarn`Failed to import ${functionName} - using existing version`;
+    } else {
+      logWarn`Failed to import ${functionName} - no prior version loaded`;
+    }
+
+    if (typeof error === 'string') {
+      console.error(color.yellow(error));
+    } else {
+      console.error(error);
+    }
+
+    return false;
+  }
+}
-- 
cgit 1.3.0-6-gf8a5