JS: Avoid materializing JSONValue.getFile()

javascript/ql/src/semmle/javascript/JSON.qll

@@ -32,6 +32,14 @@ class JSONValue extends @json_value, Locatable {
   predicate isTopLevel() { not exists(getParent()) }
 
   override string toString() { json(this, _, _, _, result) }
+
+  /** Gets the JSON file containing this value. */
+  File getJsonFile() {
+    exists(Location loc |
+      json_locations(this, loc) and
+      result = loc.getFile()
+    )
+  }
 }
 
 /**

javascript/ql/src/semmle/javascript/NPM.qll

@@ -8,7 +8,7 @@ private import NodeModuleResolutionImpl
 /** A `package.json` configuration object. */
 class PackageJSON extends JSONObject {
   PackageJSON() {
-    getFile().getBaseName() = "package.json" and
+    getJsonFile().getBaseName() = "package.json" and
     isTopLevel()
   }
 
@@ -274,7 +274,7 @@ class NPMPackage extends @folder {
   /** The `package.json` file of this package. */
   PackageJSON pkg;
 
-  NPMPackage() { pkg.getFile().getParentContainer() = this }
+  NPMPackage() { pkg.getJsonFile().getParentContainer() = this }
 
   /** Gets a textual representation of this package. */
   string toString() { result = this.(Folder).toString() }

javascript/ql/src/semmle/javascript/frameworks/Babel.qll

@@ -11,7 +11,7 @@ module Babel {
    */
   class Config extends JSONObject {
     Config() {
-      isTopLevel() and getFile().getBaseName().matches(".babelrc%")
+      isTopLevel() and getJsonFile().getBaseName().matches(".babelrc%")
       or
       this = any(PackageJSON pkg).getPropValue("babel")
     }
@@ -34,12 +34,12 @@ module Babel {
      * Gets a file affected by this Babel configuration.
      */
     Container getAContainerInScope() {
-      result = getFile().getParentContainer()
+      result = getJsonFile().getParentContainer()
       or
       result = getAContainerInScope().getAChildContainer() and
       // File-relative .babelrc search stops at any package.json or .babelrc file.
-      not result.getAChildContainer() = any(PackageJSON pkg).getFile() and
-      not result.getAChildContainer() = any(Config pkg).getFile()
+      not result.getAChildContainer() = any(PackageJSON pkg).getJsonFile() and
+      not result.getAChildContainer() = any(Config pkg).getJsonFile()
     }
 
     /**
@@ -133,7 +133,7 @@ module Babel {
     /**
      * Gets the folder in which this configuration is located.
      */
-    Folder getFolder() { result = getFile().getParentContainer() }
+    Folder getFolder() { result = getJsonFile().getParentContainer() }
   }
 
   /**