JS: Add TypedExprs metric

javascript/ql/src/meta/MetaMetrics.qll

@@ -0,0 +1,11 @@
+/**
+ * Helpers to generating meta metrics, that is, metrics about the CodeQL analysis and extractor.
+ */
+private import javascript
+
+/**
+ * Gets the root folder of the snapshot.
+ *
+ * This is selected as the location for project-wide metrics.
+ */
+Folder projectRoot() { result.getRelativePath() = "" }

javascript/ql/src/meta/analysis-quality/CallGraphQuality.qll

@@ -10,12 +10,7 @@ private import semmle.javascript.dependencies.FrameworkLibraries
 private import semmle.javascript.frameworks.Testing
 private import DataFlow
 
-/**
- * Gets the root folder of the snapshot.
- *
- * This is selected as the location for project-wide metrics.
- */
-Folder projectRoot() { result.getRelativePath() = "" }
+import meta.MetaMetrics
 
 /** A file we ignore because it is a test file or compiled/generated/bundled code. */
 class IgnoredFile extends File {

javascript/ql/src/meta/types/TypedExprs.ql

@@ -0,0 +1,19 @@
+/**
+ * @name Typed expressions
+ * @description The number of expressions for which the TypeScript extractor could
+ *              extract a type other than 'any'.
+ * @kind metric
+ * @metricType project
+ * @metricAggregate sum
+ * @tags meta
+ * @id js/meta/typed-expressions
+ */
+
+import javascript
+import meta.MetaMetrics
+
+predicate isProperType(Type t) {
+  not t instanceof AnyType
+}
+
+select projectRoot(), count(Expr e | isProperType(e.getType()))