feat(TypeMapper): add parseTypesFromString parseTypesFromAst methods

Related graphql-compose#107

Author: nodkz

src/__tests__/typeMapper-test.js

@@ -663,4 +663,30 @@ describe('TypeMapper', () => {
       expect(acm.a2.type).toBe(GraphQLInt);
     });
   });
+
+  describe('parseTypesFrom... methods', () => {
+    it('parseTypesFromString()', () => {
+      const gql = `
+        type User {
+          name: String
+        }
+
+        type Article {
+          title: String
+        }
+
+        input Record {
+          id: ID
+          ts: Int
+        }
+      `;
+
+      const ts = typeMapper.parseTypesFromString(gql);
+      expect(Array.from(ts.keys())).toEqual(['User', 'Article', 'Record']);
+
+      expect(ts.get('User')).toBeInstanceOf(GraphQLObjectType);
+      expect(ts.get('Article')).toBeInstanceOf(GraphQLObjectType);
+      expect(ts.get('Record')).toBeInstanceOf(GraphQLInputObjectType);
+    });
+  });
 });

src/typeMapper.js

@@ -87,6 +87,7 @@ import type { Thunk } from './utils/definitions';
 import TypeComposer from './typeComposer';
 import InputTypeComposer from './inputTypeComposer';
 import Resolver from './resolver';
+import TypeStorage from './typeStorage';
 import GQC from './gqc';
 
 export type TypeDefinitionString = string; // eg type Name { field: Int }
@@ -188,6 +189,27 @@ class TypeMapper {
     return undefined;
   }
 
+  parseTypesFromString(str: string): TypeStorage<GraphQLNamedType> {
+    const astDocument: DocumentNode = parse(str);
+
+    if (!astDocument || astDocument.kind !== 'Document') {
+      throw new Error('You should provide correct SDL syntax.');
+    }
+
+    return this.parseTypesFromAst(astDocument);
+  }
+
+  parseTypesFromAst(astDocument: DocumentNode): TypeStorage<GraphQLNamedType> {
+    const typeStorage = new TypeStorage();
+
+    for (let i = 0; i < astDocument.definitions.length; i++) {
+      const def = astDocument.definitions[i];
+      const type = makeSchemaDef(def);
+      typeStorage.set(type.name, type);
+    }
+    return typeStorage;
+  }
+
   convertOutputFieldConfig<TSource, TContext>(
     composeFC: ComposeFieldConfig<TSource, TContext>,
     fieldName?: string = '',