Improved parse to support converting comments into descriptions

packages/load/src/load-typedefs/parse.ts

@@ -1,6 +1,5 @@
-import { Source, printSchemaWithDirectives, fixSchemaAst } from '@graphql-tools/utils';
+import { Source, printSchemaWithDirectives, fixSchemaAst, parseGraphQLSDL } from '@graphql-tools/utils';
 import { printWithComments, resetComments } from '@graphql-tools/merge';
-import { parse, Source as GraphQLSource } from 'graphql';
 import { filterKind } from '../filter-document-kind';
 
 type Options = any;
@@ -67,7 +66,7 @@ function parseSchema(input: Input) {
 
 function parseRawSDL(input: Input) {
   if (input.source.rawSDL) {
-    input.source.document = parse(new GraphQLSource(input.source.rawSDL, input.source.location), input.options);
+    input.source.document = parseGraphQLSDL(input.source.location, input.source.rawSDL, input.options).document;
   }
 }
 

packages/loaders/graphql-file/src/index.ts

@@ -116,6 +116,7 @@ export class GraphQLFileLoader implements UniversalLoader<GraphQLFileLoaderOptio
         },
       };
     }
-    return parseGraphQLSDL(pointer, rawSDL.trim(), options);
+
+    return parseGraphQLSDL(pointer, rawSDL, options);
   }
 }

packages/schema/src/buildSchemaFromTypeDefinitions.ts

@@ -1,6 +1,6 @@
-import { parse, extendSchema, buildASTSchema, GraphQLSchema, DocumentNode, ASTNode } from 'graphql';
+import { extendSchema, buildASTSchema, GraphQLSchema, DocumentNode, ASTNode } from 'graphql';
 
-import { ITypeDefinitions, GraphQLParseOptions } from '@graphql-tools/utils';
+import { ITypeDefinitions, GraphQLParseOptions, parseGraphQLSDL } from '@graphql-tools/utils';
 
 import { extractExtensionDefinitions, filterExtensionDefinitions } from './extensionDefinitions';
 import { concatenateTypeDefs } from './concatenateTypeDefs';
@@ -33,9 +33,9 @@ export function buildDocumentFromTypeDefinitions(
 ): DocumentNode {
   let document: DocumentNode;
   if (typeof typeDefinitions === 'string') {
-    document = parse(typeDefinitions, parseOptions);
+    document = parseGraphQLSDL('', typeDefinitions, parseOptions).document;
   } else if (Array.isArray(typeDefinitions)) {
-    document = parse(concatenateTypeDefs(typeDefinitions), parseOptions);
+    document = parseGraphQLSDL('', concatenateTypeDefs(typeDefinitions), parseOptions).document;
   } else if (isDocumentNode(typeDefinitions)) {
     document = typeDefinitions;
   } else {

packages/utils/src/loaders.ts

@@ -1,5 +1,6 @@
-import { DocumentNode, GraphQLSchema, ParseOptions, BuildSchemaOptions } from 'graphql';
+import { DocumentNode, GraphQLSchema, BuildSchemaOptions } from 'graphql';
 import { GraphQLSchemaValidationOptions } from 'graphql/type/schema';
+import { ExtendedParseOptions } from './parse-graphql-sdl';
 
 export interface Source {
   document?: DocumentNode;
@@ -8,7 +9,7 @@ export interface Source {
   location?: string;
 }
 
-export type SingleFileOptions = ParseOptions &
+export type SingleFileOptions = ExtendedParseOptions &
   GraphQLSchemaValidationOptions &
   BuildSchemaOptions & {
     cwd?: string;

packages/utils/src/parse-graphql-json.ts

@@ -1,8 +1,9 @@
-import { buildClientSchema, parse, ParseOptions } from 'graphql';
+import { buildClientSchema, ParseOptions } from 'graphql';
 import { GraphQLSchemaValidationOptions } from 'graphql/type/schema';
 import { printSchemaWithDirectives } from './print-schema-with-directives';
 import { Source } from './loaders';
 import { SchemaPrintOptions } from './types';
+import { parseGraphQLSDL } from './parse-graphql-sdl';
 
 function stripBOM(content: string): string {
   content = content.toString();
@@ -44,7 +45,7 @@ export function parseGraphQLJSON(
 
     return {
       location,
-      document: parse(rawSDL, options),
+      document: parseGraphQLSDL(location, rawSDL, options).document,
       rawSDL,
       schema,
     };

packages/utils/src/parse-graphql-sdl.ts

@@ -1,9 +1,46 @@
-import { ParseOptions, DocumentNode, parse, Kind, Source as GraphQLSource } from 'graphql';
+import {
+  ParseOptions,
+  DocumentNode,
+  Kind,
+  TokenKind,
+  ASTNode,
+  parse,
+  Source as GraphQLSource,
+  visit,
+  isTypeSystemDefinitionNode,
+  StringValueNode,
+  print,
+} from 'graphql';
+import { dedentBlockStringValue } from 'graphql/language/blockString';
 
-export function parseGraphQLSDL(location: string, rawSDL: string, options: ParseOptions) {
+export interface ExtendedParseOptions extends ParseOptions {
+  /**
+   * Set to `true` in order to convert all GraphQL comments (marked with # sign) to descriptions (""")
+   * GraphQL has built-in support for transforming descriptions to comments (with `print`), but not while
+   * parsing. Turning the flag on will support the other way as well (`parse`)
+   */
+  commentDescriptions?: boolean;
+}
+
+export function parseGraphQLSDL(location: string, rawSDL: string, options: ExtendedParseOptions = {}) {
   let document: DocumentNode;
+  const sdl: string = rawSDL;
+  let sdlModified = false;
+
   try {
-    document = parse(new GraphQLSource(rawSDL, location), options);
+    if (options.commentDescriptions && sdl.includes('#')) {
+      sdlModified = true;
+      document = transformCommentsToDescriptions(rawSDL, options);
+
+      // If noLocation=true, we need to make sure to print and parse it again, to remove locations,
+      // since `transformCommentsToDescriptions` must have locations set in order to transform the comments
+      // into descriptions.
+      if (options.noLocation) {
+        document = parse(print(document), options);
+      }
+    } else {
+      document = parse(new GraphQLSource(sdl, location), options);
+    }
   } catch (e) {
     if (e.message.includes('EOF')) {
       document = {
@@ -14,9 +51,97 @@ export function parseGraphQLSDL(location: string, rawSDL: string, options: Parse
       throw e;
     }
   }
+
   return {
     location,
     document,
-    rawSDL,
+    rawSDL: sdlModified ? print(document) : sdl,
   };
 }
+
+export function getLeadingCommentBlock(node: ASTNode): void | string {
+  const loc = node.loc;
+
+  if (!loc) {
+    return;
+  }
+
+  const comments = [];
+  let token = loc.startToken.prev;
+
+  while (
+    token != null &&
+    token.kind === TokenKind.COMMENT &&
+    token.next &&
+    token.prev &&
+    token.line + 1 === token.next.line &&
+    token.line !== token.prev.line
+  ) {
+    const value = String(token.value);
+    comments.push(value);
+    token = token.prev;
+  }
+
+  return comments.length > 0 ? comments.reverse().join('\n') : undefined;
+}
+
+export function transformCommentsToDescriptions(
+  sourceSdl: string,
+  options: ExtendedParseOptions = {}
+): DocumentNode | null {
+  const parsedDoc = parse(sourceSdl, {
+    ...options,
+    noLocation: false,
+  });
+  const modifiedDoc = visit(parsedDoc, {
+    leave: (node: ASTNode) => {
+      if (isDescribable(node)) {
+        const rawValue = getLeadingCommentBlock(node);
+
+        if (rawValue !== undefined) {
+          const commentsBlock = dedentBlockStringValue('\n' + rawValue);
+          const isBlock = commentsBlock.includes('\n');
+
+          if (!node.description) {
+            return {
+              ...node,
+              description: {
+                kind: Kind.STRING,
+                value: commentsBlock,
+                block: isBlock,
+              },
+            };
+          } else {
+            return {
+              ...node,
+              description: {
+                ...node.description,
+                value: node.description.value + '\n' + commentsBlock,
+                block: true,
+              },
+            };
+          }
+        }
+      }
+    },
+  });
+
+  return modifiedDoc;
+}
+
+type DiscriminateUnion<T, U> = T extends U ? T : never;
+type DescribableASTNodes = DiscriminateUnion<
+  ASTNode,
+  {
+    description?: StringValueNode;
+  }
+>;
+
+export function isDescribable(node: ASTNode): node is DescribableASTNodes {
+  return (
+    isTypeSystemDefinitionNode(node) ||
+    node.kind === Kind.FIELD_DEFINITION ||
+    node.kind === Kind.INPUT_VALUE_DEFINITION ||
+    node.kind === Kind.ENUM_VALUE_DEFINITION
+  );
+}

packages/utils/tests/__snapshots__/parse-graphql-sdl.spec.ts.snap

@@ -0,0 +1,107 @@
+// Jest Snapshot v1, https://goo.gl/fbAQLP
+
+exports[`parse sdl comment parsing should transform comments to descriptions correctly on all available nodes 1`] = `
+"\\"test type comment\\"
+type Type {
+  \\"test field comment\\"
+  f1: String!
+  \\"\\"\\"
+   Line 1
+  Line 2
+  \\"\\"\\"
+  f2: String!
+  \\"\\"\\"
+  line 2
+  Line 1
+  \\"\\"\\"
+  f3: String!
+}
+
+extend type Type {
+  \\"test extension field comment\\"
+  f4: String!
+}
+
+type OtherType implements Node {
+  id: ID!
+  f: String!
+}
+
+\\"input test\\"
+input Input {
+  \\"Input field test\\"
+  f: String
+}
+
+\\"Enum test\\"
+enum Enum {
+  \\"Enum value test\\"
+  V1
+  V2
+}
+
+\\"Union test\\"
+union Union = Type | OtherType
+
+\\"Inferface test\\"
+interface Node {
+  id: ID!
+}
+
+\\"Custom scalar test\\"
+scalar Date
+"
+`;
+
+exports[`parse sdl comment parsing should transform comments to descriptions correctly on all available nodes with noLocation=true 1`] = `
+"\\"test type comment\\"
+type Type {
+  \\"test field comment\\"
+  f1: String!
+  \\"\\"\\"
+   Line 1
+  Line 2
+  \\"\\"\\"
+  f2: String!
+  \\"\\"\\"
+  line 2
+  Line 1
+  \\"\\"\\"
+  f3: String!
+}
+
+extend type Type {
+  \\"test extension field comment\\"
+  f4: String!
+}
+
+type OtherType implements Node {
+  id: ID!
+  f: String!
+}
+
+\\"input test\\"
+input Input {
+  \\"Input field test\\"
+  f: String
+}
+
+\\"Enum test\\"
+enum Enum {
+  \\"Enum value test\\"
+  V1
+  V2
+}
+
+\\"Union test\\"
+union Union = Type | OtherType
+
+\\"Inferface test\\"
+interface Node {
+  id: ID!
+}
+
+\\"Custom scalar test\\"
+scalar Date
+"
+`;