Started work on introspection

Author: benjie

src/type/__tests__/introspection-test.ts

@@ -26,6 +26,7 @@ describe('Introspection', () => {
       descriptions: false,
       specifiedByUrl: true,
       directiveIsRepeatable: true,
+      errorBehavior: true,
     });
 
     const result = graphqlSync({ schema, source });
@@ -35,6 +36,7 @@ describe('Introspection', () => {
           queryType: { name: 'SomeObject', kind: 'OBJECT' },
           mutationType: null,
           subscriptionType: null,
+          defaultErrorBehavior: 'PROPAGATE',
           types: [
             {
               kind: 'OBJECT',
@@ -1754,4 +1756,60 @@ describe('Introspection', () => {
     });
     expect(result).to.not.have.property('errors');
   });
+
+  it('reflects the default error behavior (default)', () => {
+    const schema = buildSchema(`
+      type SomeObject {
+        someField: String
+      }
+
+      schema {
+        query: SomeObject
+      }
+    `);
+
+    const source = getIntrospectionQuery({
+      descriptions: false,
+      specifiedByUrl: true,
+      directiveIsRepeatable: true,
+    });
+
+    const result = graphqlSync({ schema, source });
+    expect(result).to.deep.equal({
+      data: {
+        __schema: {
+          defaultErrorBehavior: 'PROPAGATE',
+        },
+      },
+    });
+  });
+
+  it('reflects the default error behavior (NO_PROPAGATE)', () => {
+    const schema = buildSchema(`
+      type SomeObject {
+        someField: String
+      }
+
+      schema @behavior(onError: NO_PROPAGATE) {
+        query: SomeObject
+      }
+    `);
+
+    const source = /* GraphQL */ `
+      {
+        __schema {
+          defaultErrorBehavior
+        }
+      }
+    `;
+
+    const result = graphqlSync({ schema, source });
+    expect(result).to.deep.equal({
+      data: {
+        __schema: {
+          defaultErrorBehavior: 'NO_PROPAGATE',
+        },
+      },
+    });
+  });
 });

src/utilities/getIntrospectionQuery.ts

@@ -38,6 +38,12 @@ export interface IntrospectionOptions {
    * Default: false
    */
   oneOf?: boolean;
+
+  /**
+   * Whether target GraphQL server supports changing error behaviors.
+   * Default: false
+   */
+  errorBehavior?: boolean;
 }
 
 /**
@@ -52,6 +58,7 @@ export function getIntrospectionQuery(options?: IntrospectionOptions): string {
     schemaDescription: false,
     inputValueDeprecation: false,
     oneOf: false,
+    errorBehavior: false,
     ...options,
   };
 
@@ -65,6 +72,9 @@ export function getIntrospectionQuery(options?: IntrospectionOptions): string {
   const schemaDescription = optionsWithDefault.schemaDescription
     ? descriptions
     : '';
+  const defaultErrorBehavior = optionsWithDefault.errorBehavior
+    ? 'defaultErrorBehavior'
+    : '';
 
   function inputDeprecation(str: string) {
     return optionsWithDefault.inputValueDeprecation ? str : '';
@@ -78,6 +88,7 @@ export function getIntrospectionQuery(options?: IntrospectionOptions): string {
         queryType { name kind }
         mutationType { name kind }
         subscriptionType { name kind }
+        ${defaultErrorBehavior}
         types {
           ...FullType
         }