chore: typescript-redux followups

federation-js/src/composition/utils.ts

@@ -147,9 +147,37 @@ function removeExternalFieldsFromExtensionVisitor<
   };
 }
 
-export function parseSelections(source: string) {
-  return (parse(`query { ${source} }`)
-    .definitions[0] as OperationDefinitionNode).selectionSet.selections;
+/**
+ * For lack of a "home of federation utilities", this function is copy/pasted
+ * verbatim across the federation, gateway, and query-planner packages. Any changes
+ * made here should be reflected in the other two locations as well.
+ *
+ * @param condition
+ * @param message
+ * @throws
+ */
+export function assert(condition: any, message: string): asserts condition {
+  if (!condition) {
+    throw new Error(message);
+  }
+}
+
+/**
+ * For lack of a "home of federation utilities", this function is copy/pasted
+ * verbatim across the federation, gateway, and query-planner packages. Any changes
+ * made here should be reflected in the other two locations as well.
+ *
+ * @param source A string representing a FieldSet
+ * @returns A parsed FieldSet
+ */
+export function parseSelections(source: string): ReadonlyArray<SelectionNode> {
+  const parsed = parse(`{${source}}`);
+  assert(
+    parsed.definitions.length === 1,
+    `Invalid FieldSet provided: '${source}'. FieldSets may not contain operations within them.`,
+  );
+  return (parsed.definitions[0] as OperationDefinitionNode).selectionSet
+    .selections;
 }
 
 export function hasMatchingFieldInDirectives({

gateway-js/src/utilities/assert.ts

@@ -0,0 +1,14 @@
+/**
+ * For lack of a "home of federation utilities", this function is copy/pasted
+ * verbatim across the federation, gateway, and query-planner packages. Any changes
+ * made here should be reflected in the other two locations as well.
+ *
+ * @param condition
+ * @param message
+ * @throws {@link Error}
+ */
+export function assert(condition: any, message: string): asserts condition {
+  if (!condition) {
+    throw new Error(message);
+  }
+}

gateway-js/src/utilities/graphql.ts

@@ -13,6 +13,7 @@ import {
   SelectionNode,
   TypeNode,
 } from 'graphql';
+import { assert } from './assert';
 
 export function getResponseName(node: FieldNode): string {
   return node.alias ? node.alias.value : node.name.value;
@@ -41,7 +42,20 @@ export function astFromType(type: GraphQLType): TypeNode {
   }
 }
 
+/**
+ * For lack of a "home of federation utilities", this function is copy/pasted
+ * verbatim across the federation, gateway, and query-planner packages. Any changes
+ * made here should be reflected in the other two locations as well.
+ *
+ * @param source A string representing a FieldSet
+ * @returns A parsed FieldSet
+ */
 export function parseSelections(source: string): ReadonlyArray<SelectionNode> {
-  return (parse(`query { ${source} }`)
-    .definitions[0] as OperationDefinitionNode).selectionSet.selections;
+  const parsed = parse(`{${source}}`);
+  assert(
+    parsed.definitions.length === 1,
+    `Invalid FieldSet provided: '${source}'. FieldSets may not contain operations within them.`,
+  );
+  return (parsed.definitions[0] as OperationDefinitionNode).selectionSet
+    .selections;
 }

query-planner-js/src/utilities/__tests__/graphql.test.ts

@@ -0,0 +1,28 @@
+import { FieldNode } from 'graphql';
+import { parseSelections } from '../graphql';
+
+describe('graphql utility functions', () => {
+  describe('parseSelections', () => {
+    it('parses a valid FieldSet', () => {
+      const fieldSet = 'foo bar';
+      const parsed = parseSelections(fieldSet);
+      expect(parsed).toHaveLength(2);
+    });
+
+    it('parses a nested FieldSet', () => {
+      const fieldSet = 'foo { bar }';
+      const parsed = parseSelections(fieldSet);
+      expect(parsed).toHaveLength(1);
+      expect((parsed[0] as FieldNode).selectionSet?.selections).toHaveLength(1);
+    });
+
+    it('throws when injecting an extra operation', () => {
+      const invalidFieldSet = 'foo } query X { bar';
+      expect(() =>
+        parseSelections(invalidFieldSet),
+      ).toThrowErrorMatchingInlineSnapshot(
+        `"Invalid FieldSet provided: 'foo } query X { bar'. FieldSets may not contain operations within them."`,
+      );
+    });
+  });
+});

query-planner-js/src/utilities/assert.ts

@@ -1,3 +1,12 @@
+/**
+ * For lack of a "home of federation utilities", this function is copy/pasted
+ * verbatim across the federation, gateway, and query-planner packages. Any changes
+ * made here should be reflected in the other two locations as well.
+ *
+ * @param condition
+ * @param message
+ * @throws
+ */
 export function assert(condition: any, message: string): asserts condition {
   if (!condition) {
     throw new Error(message);

query-planner-js/src/utilities/graphql.ts

@@ -21,7 +21,6 @@ import {
   parse,
   SchemaMetaFieldDef,
   SelectionNode,
-  SelectionSetNode,
   TypeMetaFieldDef,
   TypeNameMetaFieldDef,
   TypeNode,
@@ -96,14 +95,22 @@ export function astFromType(type: GraphQLType): TypeNode {
   }
 }
 
-export function parseSelectionSet(source: string): SelectionSetNode {
-  return (parse(`query ${source}`)
-    .definitions[0] as OperationDefinitionNode).selectionSet;
-}
-
+/**
+ * For lack of a "home of federation utilities", this function is copy/pasted
+ * verbatim across the federation, gateway, and query-planner packages. Any changes
+ * made here should be reflected in the other two locations as well.
+ *
+ * @param source A string representing a FieldSet
+ * @returns A parsed FieldSet
+ */
 export function parseSelections(source: string): ReadonlyArray<SelectionNode> {
-  return (parse(`query { ${source} }`)
-    .definitions[0] as OperationDefinitionNode).selectionSet.selections;
+  const parsed = parse(`{${source}}`);
+  assert(
+    parsed.definitions.length === 1,
+    `Invalid FieldSet provided: '${source}'. FieldSets may not contain operations within them.`,
+  );
+  return (parsed.definitions[0] as OperationDefinitionNode).selectionSet
+    .selections;
 }
 
 // Using `getArgumentValues` from `graphql-js` ensures that arguments are of the right type,