[TypeSpecValidation] Refactor package.json (#24756)

- Improves upon #24745
- Creates eng/tools/package.json for all EngSys tools
- Moves "postinstall" to eng/tools/TypeSpecValidation/package.json
  - Technically incorrect if the package were ever to be published to a registry
  - In practice, the best way I have found so far to use source-based tools in a TypeScript repo

eng/pipelines/typespec-ci.yml

@@ -40,10 +40,6 @@ jobs:
     displayName: npm ls -a
     condition: succeededOrFailed()
 
-  - script: npm run build
-    displayName: npm run build
-    condition: succeededOrFailed()
-
   - template: templates/steps/typespec-ci.yml
     parameters:
       Folder: specification/contosowidgetmanager/Contoso.WidgetManager

eng/tools/TypeSpecValidation/package.json

@@ -13,6 +13,10 @@
     },
     "devDependencies": {
         "@types/debug": "^4.1.8",
-        "@types/node": "^18.16.18"
+        "@types/node": "^18.16.18",
+        "typescript": "~5.0.4"
+    },
+    "scripts": {
+        "postinstall": "tsc"
     }
 }

eng/tools/TypeSpecValidation/tsconfig.json

@@ -3,6 +3,9 @@
   "compilerOptions": {
     "target": "ES6",
     "module": "Node16",
-    "outDir": "./dist"
+    "outDir": "./dist",
+
+    // override "importHelpers:true" in root tsconfig.json
+    "importHelpers": false
   }
 }

eng/tools/package.json

@@ -0,0 +1,7 @@
+{
+  "name": "azure-rest-api-specs-eng-tools",
+  "devDependencies": {
+    "@azure-tools/typespec-validation": "file:TypeSpecValidation"
+  },
+  "private": true
+}

package.json

@@ -12,19 +12,16 @@
     "@azure-tools/typespec-azure-resource-manager": "0.31.0",
     "@azure-tools/typespec-client-generator-core": "0.31.0",
     "@azure-tools/typespec-providerhub": "0.31.0",
-    "@azure-tools/typespec-validation": "file:eng/tools/TypeSpecValidation",
     "@typespec/compiler": "0.45.2",
     "@typespec/http": "0.45.0",
     "@typespec/openapi": "0.45.0",
     "@typespec/rest": "0.45.0",
     "@typespec/versioning": "0.45.0",
     "@azure/avocado": "^0.8.4",
     "@types/prettier": "^2.7.2",
+    "azure-rest-api-specs-eng-tools": "file:eng/tools",
     "prettier": "^2.8.8",
     "typescript": "~5.0.4"
   },
-  "scripts": {
-    "build": "npx --no tsc -- -p eng/tools/TypeSpecValidation"
-  },
   "private": true
 }