JS: Add EndsWith::Range

javascript/ql/src/semmle/javascript/StringOps.qll

@@ -343,16 +343,20 @@ module StringOps {
   /**
    * An expression that is equivalent to `A.endsWith(B)` or `!A.endsWith(B)`.
    */
-  abstract class EndsWith extends DataFlow::Node {
+  class EndsWith extends DataFlow::Node {
+    EndsWith::Range range;
+
+    EndsWith() { this = range }
+
     /**
      * Gets the `A` in `A.startsWith(B)`.
      */
-    abstract DataFlow::Node getBaseString();
+    DataFlow::Node getBaseString() { result = range.getBaseString() }
 
     /**
      * Gets the `B` in `A.startsWith(B)`.
      */
-    abstract DataFlow::Node getSubstring();
+    DataFlow::Node getSubstring() { result = range.getSubstring() }
 
     /**
      * Gets the polarity if the check.
@@ -360,37 +364,62 @@ module StringOps {
      * If the polarity is `false` the check returns `true` if the string does not end
      * with the given substring.
      */
-    boolean getPolarity() { result = true }
+    boolean getPolarity() { result = range.getPolarity() }
   }
 
-  /**
-   * A call of form `A.endsWith(B)`.
-   */
-  private class EndsWith_Native extends EndsWith, DataFlow::MethodCallNode {
-    EndsWith_Native() {
-      getMethodName() = "endsWith" and
-      getNumArgument() = 1
+  module EndsWith {
+    /**
+     * An expression that is equivalent to `A.endsWith(B)` or `!A.endsWith(B)`.
+     */
+    abstract class Range extends DataFlow::Node {
+      /**
+       * Gets the `A` in `A.startsWith(B)`.
+       */
+      abstract DataFlow::Node getBaseString();
+
+      /**
+       * Gets the `B` in `A.startsWith(B)`.
+       */
+      abstract DataFlow::Node getSubstring();
+
+      /**
+       * Gets the polarity if the check.
+       *
+       * If the polarity is `false` the check returns `true` if the string does not end
+       * with the given substring.
+       */
+      boolean getPolarity() { result = true }
     }
 
-    override DataFlow::Node getBaseString() { result = getReceiver() }
+    /**
+     * A call of form `A.endsWith(B)`.
+     */
+    private class EndsWith_Native extends Range, DataFlow::MethodCallNode {
+      EndsWith_Native() {
+        getMethodName() = "endsWith" and
+        getNumArgument() = 1
+      }
 
-    override DataFlow::Node getSubstring() { result = getArgument(0) }
-  }
+      override DataFlow::Node getBaseString() { result = getReceiver() }
 
-  /**
-   * A call of form `_.endsWith(A, B)` or `ramda.endsWith(A, B)`.
-   */
-  private class EndsWith_Library extends StartsWith, DataFlow::CallNode {
-    EndsWith_Library() {
-      getNumArgument() = 2 and
-      exists(DataFlow::SourceNode callee | this = callee.getACall() |
-        callee = LodashUnderscore::member("endsWith") or
-        callee = DataFlow::moduleMember("ramda", "endsWith")
-      )
+      override DataFlow::Node getSubstring() { result = getArgument(0) }
     }
 
-    override DataFlow::Node getBaseString() { result = getArgument(0) }
+    /**
+     * A call of form `_.endsWith(A, B)` or `ramda.endsWith(A, B)`.
+     */
+    private class EndsWith_Library extends StartsWith, DataFlow::CallNode {
+      EndsWith_Library() {
+        getNumArgument() = 2 and
+        exists(DataFlow::SourceNode callee | this = callee.getACall() |
+          callee = LodashUnderscore::member("endsWith") or
+          callee = DataFlow::moduleMember("ramda", "endsWith")
+        )
+      }
 
-    override DataFlow::Node getSubstring() { result = getArgument(1) }
+      override DataFlow::Node getBaseString() { result = getArgument(0) }
+
+      override DataFlow::Node getSubstring() { result = getArgument(1) }
+    }
   }
 }