Add node to ComplexityEstimatorArgs

README.md

@@ -100,6 +100,9 @@ type ComplexityEstimatorArgs = {
   // The GraphQLField that is being evaluated
   field: GraphQLField<any, any>,
 
+  // The GraphQL node that is being evaluated
+  node: FieldNode,
+
   // The input arguments of the field
   args: {[key: string]: any},
 

src/QueryComplexity.ts

@@ -33,6 +33,7 @@ import {
 export type ComplexityEstimatorArgs = {
   type: GraphQLCompositeType,
   field: GraphQLField<any, any>,
+  node: FieldNode,
   args: {[key: string]: any},
   childComplexity: number
 }
@@ -250,6 +251,7 @@ export default class QueryComplexity {
                 childComplexity,
                 args,
                 field,
+                node: childNode,
                 type: typeDef
               };
               const validScore = this.estimators.find(estimator => {

src/__tests__/QueryComplexity-test.ts

@@ -13,7 +13,7 @@ import {expect} from 'chai';
 
 import schema from './fixtures/schema';
 
-import ComplexityVisitor, {getComplexity} from '../QueryComplexity';
+import ComplexityVisitor, {getComplexity, ComplexityEstimator} from '../QueryComplexity';
 import {
   simpleEstimator,
   directiveEstimator,
@@ -758,4 +758,30 @@ describe('QueryComplexity analysis', () => {
     });
     expect(complexity).to.equal(41); // 1 for interface, 20 * 2 for complexScalar
   });
+
+  it('should include the current node in the estimator args', () => {
+    const ast = parse(`
+      query {
+        nonNullItem {
+          scalar
+          complexScalar
+          variableScalar(count: 10)
+        }
+      }
+    `);
+
+    const fieldCountEstimator: ComplexityEstimator = ({ node }) => {
+      if (node.selectionSet) {
+        return 10 * node.selectionSet.selections.length;
+      }
+      return 0;
+    };
+
+    const complexity = getComplexity({
+      estimators: [ fieldCountEstimator ],
+      schema,
+      query: ast
+    });
+    expect(complexity).to.equal(30); // 3 fields on nonNullItem * 10
+  });
 });