support outdir in tsconfig.json

Author: erik-krogh

javascript/ql/src/semmle/javascript/NodeJS.qll

@@ -175,6 +175,9 @@ class Require extends CallExpr, Import {
 
   override Module resolveImportedPath() {
     moduleInFile(result, load(min(int prio | moduleInFile(_, load(prio)))))
+    or
+    not exists(Module mod | moduleInFile(mod, load(_))) and
+    result = Import.super.resolveImportedPath()
   }
 
   /**

javascript/ql/src/semmle/javascript/Paths.qll

@@ -145,7 +145,11 @@ abstract class PathString extends string {
     n = 0 and result.getContainer() = root and root = getARootFolder()
     or
     exists(Path base | base = resolveUpTo(n - 1, root) |
-      exists(string next | next = getComponent(n - 1) |
+      exists(string next |
+        next = getComponent(n - 1)
+        or
+        next = getOriginalTypeScriptFolder(getComponent(n - 1), base.getContainer())
+      |
         // handle empty components and the special "." folder
         (next = "" or next = ".") and
         result = base
@@ -174,6 +178,42 @@ abstract class PathString extends string {
   Path resolve(Folder root) { result = resolveUpTo(getNumComponent(), root) }
 }
 
+/**
+ * Gets the first folder from `path`.
+ */
+bindingset[path]
+private string getRootFolderFromPath(string path) {
+  not exists(path.indexOf("/")) and result = path
+  or
+  result = path.substring(0, path.indexOf("/", 0, 0))
+}
+
+/**
+ * Gets a folder of TypeScript files that is compiled into JavaScript files in `outdir` relative to a `parent`.
+ */
+private string getOriginalTypeScriptFolder(string outdir, Folder parent) {
+  exists(JSONObject tsconfig |
+    tsconfig.getFile().getBaseName() = "tsconfig.json" and
+    tsconfig.isTopLevel() and
+    tsconfig.getFile().getParentContainer() = parent
+  |
+    outdir =
+      tsconfig
+          .getPropValue("compilerOptions")
+          .(JSONObject)
+          .getPropValue("outDir")
+          .(JSONString)
+          .getValue() and
+    result =
+      getRootFolderFromPath(tsconfig
+            .getPropValue("include")
+            .(JSONArray)
+            .getElementValue(_)
+            .(JSONString)
+            .getValue())
+  )
+}
+
 /**
  * An expression whose value represents a (relative or absolute) file system path.
  *