Remove deepmerge-ts for simpler implementation (#8086)

packages/astro/package.json

@@ -137,7 +137,6 @@
  "common-ancestor-path": "^1.0.1",
  "cookie": "^0.5.0",
  "debug": "^4.3.4",
- "deepmerge-ts": "^4.3.0",
  "devalue": "^4.3.2",
  "diff": "^5.1.0",
  "es-module-lexer": "^1.3.0",

packages/astro/src/core/config/tsconfig.ts

@@ -1,4 +1,3 @@
-import { deepmerge } from 'deepmerge-ts';
 import { existsSync } from 'node:fs';
 import { join } from 'node:path';
 import * as tsr from 'tsconfig-resolver';
@@ -96,5 +95,28 @@ export function updateTSConfigForFramework(
  return target;
  }
 
- return deepmerge(target, presets.get(framework)!);
+ return deepMergeObjects(target, presets.get(framework)!);
+}
+
+// Simple deep merge implementation that merges objects and strings
+function deepMergeObjects<T extends Record<string, any>>(a: T, b: T): T {
+ const merged: T = { ...a };
+
+ for (const key in b) {
+ const value = b[key];
+
+ if (a[key] == null) {
+ merged[key] = value;
+ continue;
+ }
+
+ if (typeof a[key] === 'object' && typeof value === 'object') {
+ merged[key] = deepMergeObjects(a[key], value);
+ continue;
+ }
+
+ merged[key] = value;
+ }
+
+ return merged;
 }