TS: Fix crash in case of missing type roots

javascript/extractor/lib/typescript/src/main.ts

@@ -272,7 +272,9 @@ function handleOpenProjectCommand(command: OpenProjectCommand) {
     });
 
     for (let typeRoot of typeRoots || []) {
-        traverseTypeRoot(typeRoot, "");
+        if (fs.existsSync(typeRoot) && fs.statSync(typeRoot).isDirectory()) {
+            traverseTypeRoot(typeRoot, "");
+        }
     }
 
     for (let sourceFile of program.getSourceFiles()) {

javascript/ql/test/library-tests/TypeScript/RegressionTests/MissingTypeRoot/test.expected

@@ -0,0 +1 @@
+| tst.ts:0:0:0:0 | tst.ts |

javascript/ql/test/library-tests/TypeScript/RegressionTests/MissingTypeRoot/test.ql

@@ -0,0 +1,4 @@
+import javascript
+
+from File file
+select file

javascript/ql/test/library-tests/TypeScript/RegressionTests/MissingTypeRoot/tsconfig.json

@@ -0,0 +1,6 @@
+{
+    "include": ["."],
+    "compilerOptions": {
+        "typeRoots": ["does-not-exist"]
+    }
+}

javascript/ql/test/library-tests/TypeScript/RegressionTests/MissingTypeRoot/tst.ts

@@ -0,0 +1 @@
+let x = 5;

javascript/ql/test/library-tests/TypeScript/RegressionTests/TypeRootFile/test.expected

@@ -0,0 +1,2 @@
+| tst.ts:0:0:0:0 | tst.ts |
+| typeroot.d.ts:0:0:0:0 | typeroot.d.ts |

javascript/ql/test/library-tests/TypeScript/RegressionTests/TypeRootFile/test.ql

@@ -0,0 +1,4 @@
+import javascript
+
+from File file
+select file

javascript/ql/test/library-tests/TypeScript/RegressionTests/TypeRootFile/tsconfig.json

@@ -0,0 +1,6 @@
+{
+    "include": ["."],
+    "compilerOptions": {
+        "typeRoots": ["typeroot.d.ts"]
+    }
+}

javascript/ql/test/library-tests/TypeScript/RegressionTests/TypeRootFile/tst.ts

@@ -0,0 +1 @@
+let x = 5;