support for sorting schemas

src/__tests__/diff.test.ts

@@ -221,4 +221,25 @@ describe('getDiff', () => {
       }
     });
   });
+
+  describe('schema sorting', () => {
+    it('returns diff between two unsorted, but otherwise equal schemas, when sorting not enabled', async () => {
+      const result = await getDiff(
+        path.join(__dirname, 'fixtures/localSchemaSorted.graphql'),
+        path.join(__dirname, 'fixtures/localSchemaUnsorted.graphql')
+      );
+
+      expect(result).toBeDefined();
+    });
+
+    it('returns nothing between two unsorted, but otherwise equal schemas, when sorting enabled', async () => {
+      const result = await getDiff(
+        path.join(__dirname, 'fixtures/localSchemaSorted.graphql'),
+        path.join(__dirname, 'fixtures/localSchemaUnsorted.graphql'),
+        { sortSchema: true }
+      );
+
+      expect(result).toBeUndefined();
+    });
+  });
 });

src/__tests__/fixtures/localSchemaSorted.graphql

@@ -0,0 +1,4 @@
+type Query {
+  test1: String
+  test2: String
+}

src/__tests__/fixtures/localSchemaUnsorted.graphql

@@ -0,0 +1,4 @@
+type Query {
+  test2: String
+  test1: String
+}

src/cli.ts

@@ -18,6 +18,7 @@ const cli = meow(
     --header, -H  Header to send to all remote schema sources
     --left-schema-header  Header to send to left remote schema source
     --right-schema-header Header to send to right remote schema source
+    --sort-schema, -s Sort schemas prior to diffing
 
   Examples
     $ graphql-schema-diff https://example.com/graphql schema.graphql
@@ -47,6 +48,10 @@ const cli = meow(
       },
       'right-schema-header': {
         type: 'string'
+      },
+      'sort-schema': {
+        type: 'boolean',
+        alias: 's'
       }
     }
   }
@@ -96,7 +101,8 @@ getDiff(leftSchemaLocation, rightSchemaLocation, {
   },
   rightSchema: {
     headers: parseHeaders(rightSchemaHeader)
-  }
+  },
+  sortSchema: cli.flags.sortSchema
 })
   .then(async result => {
     if (result === undefined) {

src/diff.ts

@@ -10,6 +10,7 @@ import {
   introspectionFromSchema,
   getIntrospectionQuery
 } from 'graphql';
+import { lexicographicSortSchema } from 'graphql/utilities';
 import fs from 'fs';
 import isGlob from 'is-glob';
 import fetch from 'node-fetch';
@@ -63,7 +64,9 @@ function readLocalSchema(schemaPath: string): GraphQLSchema {
   }
 
   const schema = buildSchema(schemaString);
-  const introspection = introspectionFromSchema(schema, { descriptions: false })
+  const introspection = introspectionFromSchema(schema, {
+    descriptions: false
+  });
   return buildClientSchema(introspection);
 }
 
@@ -93,6 +96,7 @@ export interface DiffOptions {
     headers?: Headers;
   };
   headers?: Headers;
+  sortSchema?: boolean;
 }
 
 export async function getDiff(
@@ -112,7 +116,7 @@ export async function getDiff(
       ...(options.rightSchema && options.rightSchema.headers)
     }
   };
-  const [leftSchema, rightSchema] = await Promise.all([
+  let [leftSchema, rightSchema] = await Promise.all([
     getSchema(leftSchemaLocation, leftSchemaOptions),
     getSchema(rightSchemaLocation, rightSchemaOptions)
   ]);
@@ -121,6 +125,13 @@ export async function getDiff(
     throw new Error('Schemas not defined');
   }
 
+  if (options.sortSchema) {
+    [leftSchema, rightSchema] = [
+      lexicographicSortSchema(leftSchema),
+      lexicographicSortSchema(rightSchema)
+    ];
+  }
+
   const [leftSchemaSDL, rightSchemaSDL] = [
     printSchema(leftSchema),
     printSchema(rightSchema)