refactor(transforms)

use delegationContext within delegation transforms
remove fragment hints and transforms in favor of selection set hints and transforms
prune fragment functions from utils package

Author: yaacovCR

packages/delegate/src/delegateToSchema.ts

@@ -23,6 +23,7 @@ import {
   SubschemaConfig,
   ExecutionParams,
   Transform,
+  StitchingInfo,
 } from './types';
 
 import { isSubschemaConfig } from './Subschema';
@@ -136,6 +137,8 @@ export function delegateRequest({
     allTransforms = transforms;
   }
 
+  const stitchingInfo: StitchingInfo = info?.schema.extensions?.stitchingInfo;
+
   const delegationContext = {
     subschema: subschemaOrSubschemaConfig,
     targetSchema,
@@ -147,7 +150,9 @@ export function delegateRequest({
     returnType:
       returnType ?? info?.returnType ?? getDelegationReturnType(targetSchema, targetOperation, targetFieldName),
     transforms: allTransforms,
-    transformedSchema: transformedSchema ?? targetSchema,
+    transformedSchema:
+      transformedSchema ??
+      (stitchingInfo ? stitchingInfo.transformedSchemas.get(subschemaOrSubschemaConfig) : targetSchema),
     skipTypeMerging,
   };
 

packages/delegate/src/delegationBindings.ts

@@ -4,71 +4,39 @@ import AddSelectionSets from './transforms/AddSelectionSets';
 import ExpandAbstractTypes from './transforms/ExpandAbstractTypes';
 import WrapConcreteTypes from './transforms/WrapConcreteTypes';
 import FilterToSchema from './transforms/FilterToSchema';
-import AddFragmentsByField from './transforms/AddFragmentsByField';
 import AddTypenameToAbstract from './transforms/AddTypenameToAbstract';
 import CheckResultAndHandleErrors from './transforms/CheckResultAndHandleErrors';
 import AddArgumentsAsVariables from './transforms/AddArgumentsAsVariables';
 
 export function defaultDelegationBinding(delegationContext: DelegationContext): Array<Transform> {
-  const {
-    subschema: schemaOrSubschemaConfig,
-    targetSchema,
-    fieldName,
-    args,
-    context,
-    info,
-    returnType,
-    transforms = [],
-    skipTypeMerging,
-  } = delegationContext;
-  const stitchingInfo: StitchingInfo = info?.schema.extensions?.stitchingInfo;
+  let delegationTransforms: Array<Transform> = [new CheckResultAndHandleErrors()];
 
-  let transformedSchema = stitchingInfo?.transformedSchemas.get(schemaOrSubschemaConfig);
-  if (transformedSchema != null) {
-    delegationContext.transformedSchema = transformedSchema;
-  } else {
-    transformedSchema = delegationContext.transformedSchema;
-  }
-
-  let delegationTransforms: Array<Transform> = [
-    new CheckResultAndHandleErrors(info, fieldName, schemaOrSubschemaConfig, context, returnType, skipTypeMerging),
-  ];
+  const info = delegationContext.info;
+  const stitchingInfo: StitchingInfo = info?.schema.extensions?.stitchingInfo;
 
   if (stitchingInfo != null) {
     delegationTransforms = delegationTransforms.concat([
-      new AddSelectionSets(
-        info.schema,
-        returnType,
-        {},
-        stitchingInfo.selectionSetsByField,
-        stitchingInfo.dynamicSelectionSetsByField
-      ),
-      new WrapConcreteTypes(returnType, transformedSchema),
-      new ExpandAbstractTypes(info.schema, transformedSchema),
+      new AddSelectionSets({}, stitchingInfo.selectionSetsByField, stitchingInfo.dynamicSelectionSetsByField),
+      new WrapConcreteTypes(),
+      new ExpandAbstractTypes(),
     ]);
   } else if (info != null) {
-    delegationTransforms = delegationTransforms.concat([
-      new WrapConcreteTypes(returnType, transformedSchema),
-      new ExpandAbstractTypes(info.schema, transformedSchema),
-    ]);
+    delegationTransforms = delegationTransforms.concat([new WrapConcreteTypes(), new ExpandAbstractTypes()]);
   } else {
-    delegationTransforms.push(new WrapConcreteTypes(returnType, transformedSchema));
+    delegationTransforms.push(new WrapConcreteTypes());
   }
 
-  delegationTransforms = delegationTransforms.concat(transforms.slice().reverse());
-
-  if (stitchingInfo != null) {
-    delegationTransforms.push(new AddFragmentsByField(targetSchema, stitchingInfo.fragmentsByField));
+  const transforms = delegationContext.transforms;
+  if (transforms != null) {
+    delegationTransforms = delegationTransforms.concat(transforms.slice().reverse());
   }
 
+  const args = delegationContext.args;
   if (args != null) {
-    delegationTransforms.push(new AddArgumentsAsVariables(targetSchema, args));
+    delegationTransforms.push(new AddArgumentsAsVariables(args));
   }
 
-  delegationTransforms = delegationTransforms.concat([
-    new FilterToSchema(targetSchema),
-    new AddTypenameToAbstract(targetSchema),
-  ]);
+  delegationTransforms = delegationTransforms.concat([new FilterToSchema(), new AddTypenameToAbstract()]);
 
   return delegationTransforms;
 }

packages/delegate/src/transforms/AddArgumentsAsVariables.ts

@@ -17,11 +17,9 @@ import { Request, serializeInputValue, updateArgument } from '@graphql-tools/uti
 import { Transform, DelegationContext } from '../types';
 
 export default class AddArgumentsAsVariables implements Transform {
-  private readonly targetSchema: GraphQLSchema;
   private readonly args: Record<string, any>;
 
-  constructor(targetSchema: GraphQLSchema, args: Record<string, any>) {
-    this.targetSchema = targetSchema;
+  constructor(args: Record<string, any>) {
     this.args = Object.entries(args).reduce(
       (prev, [key, val]) => ({
         ...prev,
@@ -33,10 +31,10 @@ export default class AddArgumentsAsVariables implements Transform {
 
   public transformRequest(
     originalRequest: Request,
-    _delegationContext: DelegationContext,
+    delegationContext: DelegationContext,
     _transformationContext: Record<string, any>
   ): Request {
-    const { document, variables } = addVariablesToRootField(this.targetSchema, originalRequest, this.args);
+    const { document, variables } = addVariablesToRootField(delegationContext.targetSchema, originalRequest, this.args);
 
     return {
       ...originalRequest,

packages/delegate/src/transforms/AddFragmentsByField.ts

@@ -1,13 +1,4 @@
-import {
-  GraphQLSchema,
-  SelectionSetNode,
-  TypeInfo,
-  GraphQLOutputType,
-  Kind,
-  FieldNode,
-  SelectionNode,
-  print,
-} from 'graphql';
+import { SelectionSetNode, TypeInfo, Kind, FieldNode, SelectionNode, print } from 'graphql';
 
 import { Request } from '@graphql-tools/utils';
 
@@ -20,13 +11,11 @@ export default class AddSelectionSets implements Transform {
   private readonly transformer: VisitSelectionSets;
 
   constructor(
-    sourceSchema: GraphQLSchema,
-    initialType: GraphQLOutputType,
     selectionSetsByType: Record<string, SelectionSetNode>,
     selectionSetsByField: Record<string, Record<string, SelectionSetNode>>,
     dynamicSelectionSetsByField: Record<string, Record<string, Array<(node: FieldNode) => SelectionSetNode>>>
   ) {
-    this.transformer = new VisitSelectionSets(sourceSchema, initialType, (node, typeInfo) =>
+    this.transformer = new VisitSelectionSets((node, typeInfo) =>
       visitSelectionSet(node, typeInfo, selectionSetsByType, selectionSetsByField, dynamicSelectionSetsByField)
     );
   }