Add getDescription.js

Author: migueloller

src/build/__tests__/getDescription-test.js

@@ -0,0 +1,26 @@
+/* @flow */
+
+import { parse } from 'graphql/language';
+import getDescription from '../getDescription';
+
+describe('getDescription()', () => {
+  const generateNode = description => parse(`
+    # ${description === undefined ? '' : description}
+    type Type {
+      int: Int
+    }
+  `).definitions[0];
+
+  test('gets description', () => {
+    const description = 'A description.';
+    expect(getDescription(generateNode(description))).toBe(description);
+  });
+
+  test('returns undefined if there\'s no description', () => {
+    expect(getDescription(generateNode())).toBeUndefined();
+  });
+
+  test('return undefined if there\'s an empty description', () => {
+    expect(getDescription(generateNode(' '))).toBeUndefined();
+  });
+});

src/build/getDescription.js

@@ -0,0 +1,8 @@
+/* @flow */
+
+import type { Location } from 'graphql/language';
+import { getDescription as get } from 'graphql/utilities/buildASTSchema';
+
+export default function getDescription(node: { loc?: Location }) {
+  return get(node) || undefined;
+}