feat(hmr): add syntax output for build errors (#1083)

Co-authored-by: Shigma <[email protected]>

plugins/hmr/package.json

@@ -44,10 +44,13 @@
     "koishi": "^4.12.7"
   },
   "devDependencies": {
+    "@types/babel__code-frame": "^7.0.3",
     "@types/throttle-debounce": "^2.1.0",
+    "esbuild": "^0.17.18",
     "koishi": "^4.12.7"
   },
   "dependencies": {
+    "@babel/code-frame": "^7.21.4",
     "chokidar": "^3.5.3",
     "throttle-debounce": "^3.0.1"
   }

plugins/hmr/src/error.ts

@@ -0,0 +1,37 @@
+import { Logger } from 'koishi'
+import { BuildFailure } from 'esbuild'
+import { codeFrameColumns } from '@babel/code-frame'
+import { readFileSync } from 'fs'
+
+const logger = new Logger('watch')
+
+function isBuildFailure(e: any): e is BuildFailure {
+  return Array.isArray(e?.errors) && e.errors.every((error: any) => error.text)
+}
+
+export function handleError(e: any) {
+  if (!isBuildFailure(e)) {
+    logger.warn(e)
+    return
+  }
+
+  for (const error of e.errors) {
+    if (!error.location) {
+      logger.warn(error.text)
+      continue
+    }
+    try {
+      const { file, line, column } = error.location
+      const source = readFileSync(file, 'utf8')
+      const formatted = codeFrameColumns(source, {
+        start: { line, column },
+      }, {
+        highlightCode: true,
+        message: error.text,
+      })
+      logger.warn(`File: ${file}:${line}:${column}\n` + formatted)
+    } catch (e) {
+      logger.warn(e)
+    }
+  }
+}

plugins/hmr/src/index.ts

@@ -3,6 +3,7 @@ import { FSWatcher, watch, WatchOptions } from 'chokidar'
 import { relative, resolve } from 'path'
 import { debounce } from 'throttle-debounce'
 import { Loader, unwrapExports } from '@koishijs/loader'
+import { handleError } from './error'
 
 declare module 'koishi' {
   interface Context {
@@ -259,8 +260,8 @@ class Watcher {
       for (const [, { filename }] of reloads) {
         attempts[filename] = unwrapExports(require(filename))
       }
-    } catch (err) {
-      logger.warn(err)
+    } catch (e) {
+      handleError(e)
       return rollback()
     }