JS: Port tutorial query4

Author: asgerf

javascript/ql/test/tutorials/Analyzing data flow in JavaScript/Global data flow/query4.ql

@@ -1,17 +1,15 @@
 import javascript
 
-class CommandLineFileNameConfiguration extends TaintTracking::Configuration {
-  CommandLineFileNameConfiguration() { this = "CommandLineFileNameConfiguration" }
-
-  override predicate isSource(DataFlow::Node source) {
+module CommandLineFileNameConfig implements DataFlow::ConfigSig {
+  predicate isSource(DataFlow::Node source) {
     DataFlow::globalVarRef("process").getAPropertyRead("argv").getAPropertyRead() = source
   }
 
-  override predicate isSink(DataFlow::Node sink) {
+  predicate isSink(DataFlow::Node sink) {
     DataFlow::moduleMember("fs", "readFile").getACall().getArgument(0) = sink
   }
 
-  override predicate isAdditionalTaintStep(DataFlow::Node pred, DataFlow::Node succ) {
+  predicate isAdditionalFlowStep(DataFlow::Node pred, DataFlow::Node succ) {
     exists(DataFlow::CallNode c |
       c = DataFlow::moduleImport("resolve-symlinks").getACall() and
       pred = c.getArgument(0) and
@@ -20,6 +18,8 @@ class CommandLineFileNameConfiguration extends TaintTracking::Configuration {
   }
 }
 
-from CommandLineFileNameConfiguration cfg, DataFlow::Node source, DataFlow::Node sink
-where cfg.hasFlow(source, sink)
+module CommandLineFileNameFlow = TaintTracking::Global<CommandLineFileNameConfig>;
+
+from DataFlow::Node source, DataFlow::Node sink
+where CommandLineFileNameFlow::flow(source, sink)
 select source, sink