Adds options for configuring the snapshot and inline snapshot serializers

CHANGELOG.md

@@ -2,6 +2,9 @@
 
 ### Features
 
+- `[jest-cli]` Adds an option (`inlineSnapshotFormatter` with `simple`) for having inline snapshot serializers use the printBasicPrototype option to show literals as literals.  ([#11654](https://github.com/facebook/jest/pull/11654))
+
+
 ### Fixes
 
 ### Chore & Maintenance

e2e/snapshot-inline-basic-formatting/__tests__/snapshot.test.js

@@ -0,0 +1,25 @@
+/**
+ * Copyright (c) Facebook, Inc. and its affiliates. All Rights Reserved.
+ *
+ * This source code is licensed under the MIT license found in the
+ * LICENSE file in the root directory of this source tree.
+ *
+ */
+'use strict';
+
+describe('inline snapshot serializer', () => {
+  it('does not show prototypes for object and array', () => {
+    const object = {
+      array: [{hello: 'Danger'}],
+    };
+    expect(object).toMatchInlineSnapshot(`
+{
+  "array": [
+    {
+      "hello": "Danger",
+    },
+  ],
+}
+`);
+  });
+});

e2e/snapshot-inline-basic-formatting/package.json

@@ -0,0 +1,6 @@
+{
+  "jest": {
+    "testEnvironment": "node",
+    "inlineSnapshotFormatter": "simple"
+  }
+}

packages/jest-circus/src/legacy-code-todo-rewrite/jestAdapterInit.ts

@@ -155,6 +155,7 @@ export const initialize = async ({
   const snapshotPath = snapshotResolver.resolveSnapshotPath(testPath);
   const snapshotState = new SnapshotState(snapshotPath, {
     expand,
+    preferSimpleForInline: config.inlineSnapshotFormatter === 'simple',
     prettierPath: config.prettierPath,
     updateSnapshot,
   });

packages/jest-config/src/ValidConfig.ts

@@ -66,6 +66,10 @@ const initialOptions: Config.InitialOptions = {
     throwOnModuleCollision: false,
   },
   injectGlobals: true,
+  inlineSnapshotFormatter: multipleValidOptions(
+    'exposed prototypes',
+    'simple',
+  ) as any,
   json: false,
   lastCommit: false,
   listTests: false,

packages/jest-config/src/index.ts

@@ -127,6 +127,7 @@ const groupOptions = (
     forceExit: options.forceExit,
     globalSetup: options.globalSetup,
     globalTeardown: options.globalTeardown,
+    inlineSnapshotFormatter: options.inlineSnapshotFormatter,
     json: options.json,
     lastCommit: options.lastCommit,
     listTests: options.listTests,
@@ -184,6 +185,7 @@ const groupOptions = (
     globals: options.globals,
     haste: options.haste,
     injectGlobals: options.injectGlobals,
+    inlineSnapshotFormatter: options.inlineSnapshotFormatter,
     moduleDirectories: options.moduleDirectories,
     moduleFileExtensions: options.moduleFileExtensions,
     moduleLoader: options.moduleLoader,

packages/jest-snapshot/src/State.ts

@@ -25,6 +25,7 @@ export type SnapshotStateOptions = {
   updateSnapshot: Config.SnapshotUpdateState;
   prettierPath: Config.Path;
   expand?: boolean;
+  preferSimpleForInline?: boolean;
 };
 
 export type SnapshotMatchOptions = {
@@ -61,6 +62,7 @@ export default class SnapshotState {
   private _inlineSnapshots: Array<InlineSnapshot>;
   private _uncheckedKeys: Set<string>;
   private _prettierPath: Config.Path;
+  private _preferSimpleInlineSnapshots: boolean;
 
   added: number;
   expand: boolean;
@@ -88,6 +90,7 @@ export default class SnapshotState {
     this.unmatched = 0;
     this._updateSnapshot = options.updateSnapshot;
     this.updated = 0;
+    this._preferSimpleInlineSnapshots = options.preferSimpleForInline || false;
   }
 
   markSnapshotsAsCheckedForTest(testName: string): void {
@@ -201,7 +204,14 @@ export default class SnapshotState {
       this._uncheckedKeys.delete(key);
     }
 
-    const receivedSerialized = addExtraLineBreaks(serialize(received));
+    // There is an option to allow for not showing 'Object' and 'Array' on
+    // snapshots, which we'd like to allow for opting into with inline snapshots.
+    const hasOptedInToSimpleInline =
+      isInline && this._preferSimpleInlineSnapshots;
+
+    const receivedSerialized = addExtraLineBreaks(
+      serialize(received, undefined, hasOptedInToSimpleInline),
+    );
     const expected = isInline ? inlineSnapshot : this._snapshotData[key];
     const pass = expected === receivedSerialized;
     const hasSnapshot = expected !== undefined;

packages/jest-snapshot/src/utils.ts

@@ -152,12 +152,17 @@ export const removeLinesBeforeExternalMatcherTrap = (stack: string): string => {
 const escapeRegex = true;
 const printFunctionName = false;
 
-export const serialize = (val: unknown, indent = 2): string =>
+export const serialize = (
+  val: unknown,
+  indent = 2,
+  printBasicPrototype: boolean = true,
+): string =>
   normalizeNewlines(
     prettyFormat(val, {
       escapeRegex,
       indent,
       plugins: getSerializers(),
+      printBasicPrototype,
       printFunctionName,
     }),
   );

packages/jest-types/src/Config.ts

@@ -171,6 +171,7 @@ export type InitialOptions = Partial<{
   globalTeardown: string | null | undefined;
   haste: HasteConfig;
   injectGlobals: boolean;
+  inlineSnapshotFormatter: 'exposed prototypes' | 'simple';
   reporters: Array<string | ReporterConfig>;
   logHeapUsage: boolean;
   lastCommit: boolean;
@@ -292,6 +293,7 @@ export type GlobalConfig = {
   json: boolean;
   globalSetup?: string;
   globalTeardown?: string;
+  inlineSnapshotFormatter: 'exposed prototypes' | 'simple';
   lastCommit: boolean;
   logHeapUsage: boolean;
   listTests: boolean;
@@ -352,6 +354,7 @@ export type ProjectConfig = {
   globalTeardown?: string;
   globals: ConfigGlobals;
   haste: HasteConfig;
+  inlineSnapshotFormatter: 'exposed prototypes' | 'simple';
   injectGlobals: boolean;
   moduleDirectories: Array<string>;
   moduleFileExtensions: Array<string>;

packages/test-utils/src/config.ts

@@ -27,6 +27,7 @@ const DEFAULT_GLOBAL_CONFIG: Config.GlobalConfig = {
   forceExit: false,
   globalSetup: undefined,
   globalTeardown: undefined,
+  inlineSnapshotFormatter: 'exposed prototypes',
   json: false,
   lastCommit: false,
   listTests: false,
@@ -84,6 +85,7 @@ const DEFAULT_PROJECT_CONFIG: Config.ProjectConfig = {
   globals: {},
   haste: {},
   injectGlobals: true,
+  inlineSnapshotFormatter: 'exposed prototypes',
   moduleDirectories: [],
   moduleFileExtensions: ['js'],
   moduleLoader: '/test_module_loader_path',