Export complexity directive

src/estimators/directive/README.md

@@ -63,3 +63,19 @@ input Filter {
 ```
 
 The multipliers can be combined. Configured multipliers that don't have a value or `NULL` are ignored. 
+
+Code first approach can use the `createComplexityDirective` function to generate directive definition:
+
+```typescript
+import {createComplexityDirective} from 'graphql-query-complexity';
+
+const schema = new GraphQLSchema({
+  directives: [
+    createComplexityDirective({
+      // Optionally change the name of the directive here... Default value is `complexity`
+      name: 'complexity'
+    })
+  ]
+  // ... other config
+});
+```

src/estimators/directive/__tests__/directiveEstimator-test.ts

@@ -3,18 +3,22 @@
  */
 
 import {
+  GraphQLSchema,
   parse,
+  print,
+  printSchema,
   TypeInfo,
   visit,
   visitWithTypeInfo,
+  buildSchema
 } from 'graphql';
 
 import {expect} from 'chai';
 
 import schema from './fixtures/schema';
 
 import ComplexityVisitor from '../../../QueryComplexity';
-import directiveEstimator from '../index';
+import directiveEstimator, {createComplexityDirective} from '../index';
 import { CompatibleValidationContext } from '../../../__tests__/fixtures/CompatibleValidationContext';
 
 describe('directiveEstimator analysis', () => {
@@ -224,7 +228,7 @@ describe('directiveEstimator analysis', () => {
     expect(visitor.complexity).to.equal(10);
   });
 
-  it('ignores fields without compexity directive', () => {
+  it('ignores fields without complexity directive', () => {
     const ast = parse(`
       query {
         noDirective
@@ -245,4 +249,38 @@ describe('directiveEstimator analysis', () => {
       'No complexity could be calculated for field Query.noDirective',
     );
   });
+
+  it('should create complexity directive that can be used to generate directive definition', () => {
+    const complexityDirective = createComplexityDirective();
+    const codeFirstSchema = new GraphQLSchema({
+      directives: [complexityDirective]
+    });
+
+    // rebuilding code first schema
+    // graphql-js <= 14 prints descriptions in different ways printSchema(schema) vs print(astNode)
+    // and directive from code first schema has no astNode
+    const builtCodeFirstSchema = buildSchema(printSchema(codeFirstSchema));
+
+    const printedSchemaFirstDirective = print(schema.getDirective('complexity').astNode);
+    const printedCodeFirstDirective = print(builtCodeFirstSchema.getDirective('complexity').astNode);
+
+    expect(printedSchemaFirstDirective).to.equal(printedCodeFirstDirective);
+  });
+
+  it('should create complexity directive with configured name', () => {
+    const complexityDirective = createComplexityDirective({name: 'cost'});
+    const codeFirstSchema = new GraphQLSchema({
+      directives: [complexityDirective]
+    });
+
+    // rebuilding code first schema
+    // graphql-js <= 14 prints descriptions in different ways printSchema(schema) vs print(astNode)
+    // and directive from code first schema has no astNode
+    const builtCodeFirstSchema = buildSchema(printSchema(codeFirstSchema));
+
+    const printedSchemaFirstDirective = print(schema.getDirective('cost').astNode);
+    const printedCodeFirstDirective = print(builtCodeFirstSchema.getDirective('cost').astNode);
+
+    expect(printedSchemaFirstDirective).to.equal(printedCodeFirstDirective);
+  });
 });

src/estimators/directive/__tests__/fixtures/schema.ts

@@ -7,12 +7,16 @@ import {
 } from 'graphql';
 
 export default buildSchema(`
+"""Define a relation between the field and other nodes"""
 directive @cost(
+  """The complexity value for the field"""
   value: Int!,
   multipliers: [String!]
 ) on FIELD_DEFINITION
 
+"""Define a relation between the field and other nodes"""
 directive @complexity(
+  """The complexity value for the field"""
   value: Int!,
   multipliers: [String!]
 ) on FIELD_DEFINITION

src/estimators/directive/index.ts

@@ -4,17 +4,21 @@ import { GraphQLDirective } from 'graphql/type/directives';
 import { DirectiveLocation } from 'graphql/language/directiveLocation';
 import get from 'lodash.get';
 
-export default function (options?: {}): ComplexityEstimator {
+export type ComplexityDirectiveOptions = {
+  name?: string
+}
+
+export function createComplexityDirective(options?: ComplexityDirectiveOptions) {
   const mergedOptions = {
     name: 'complexity',
     ...(options || {})
   };
 
-  const directive = new GraphQLDirective({
+  return new GraphQLDirective({
     name: mergedOptions.name,
     description: 'Define a relation between the field and other nodes',
     locations: [
-      DirectiveLocation.FIELD,
+      DirectiveLocation.FIELD_DEFINITION,
     ],
     args: {
       value: {
@@ -26,6 +30,10 @@ export default function (options?: {}): ComplexityEstimator {
       }
     },
   });
+}
+
+export default function (options: ComplexityDirectiveOptions = {}): ComplexityEstimator {
+  const directive = createComplexityDirective(options);
 
   return (args: ComplexityEstimatorArgs) => {
     // Ignore if astNode is undefined

src/estimators/index.ts

@@ -1,3 +1,3 @@
 export {default as simpleEstimator} from './simple';
-export {default as directiveEstimator} from './directive';
+export {default as directiveEstimator, ComplexityDirectiveOptions, createComplexityDirective} from './directive';
 export {default as fieldExtensionsEstimator} from './fieldExtensions';