[jest-get-type] Add isPrimitive function

CHANGELOG.md

@@ -8,7 +8,8 @@
 - `[expect]`: Improve report when matcher fails, part 10 ([#7960](https://github.com/facebook/jest/pull/7960))
 - `[pretty-format]` Support `React.memo` ([#7891](https://github.com/facebook/jest/pull/7891))
 - `[jest-config]` Print error information on preset normalization error ([#7935](https://github.com/facebook/jest/pull/7935))
-- `[jest-haste-map]` Add "skipPackageJson" option
+- `[jest-haste-map]` Add `skipPackageJson` option ([#7778](https://github.com/facebook/jest/pull/7778))
+- `[jest-get-type]` Add `isPrimitive` function ([#7708](https://github.com/facebook/jest/pull/7708))
 
 ### Fixes
 

packages/jest-each/src/bind.js

@@ -10,7 +10,7 @@
 import util from 'util';
 import chalk from 'chalk';
 import pretty from 'pretty-format';
-import getType from 'jest-get-type';
+import {isPrimitive} from 'jest-get-type';
 import {ErrorWithStack} from 'jest-util';
 
 type Table = Array<Array<any>>;
@@ -24,13 +24,6 @@ const RECEIVED_COLOR = chalk.red;
 const SUPPORTED_PLACEHOLDERS = /%[sdifjoOp%]/g;
 const PRETTY_PLACEHOLDER = '%p';
 const INDEX_PLACEHOLDER = '%#';
-const PRIMITIVES = new Set([
-  'string',
-  'number',
-  'boolean',
-  'null',
-  'undefined',
-]);
 
 export default (cb: Function, supportsDone: boolean = true) => (...args: any) =>
   function eachBind(title: string, test: Function, timeout: number): void {
@@ -203,10 +196,9 @@ const getMatchingKeyPaths = title => (matches, key) =>
 const replaceKeyPathWithValue = data => (title, match) => {
   const keyPath = match.replace('$', '').split('.');
   const value = getPath(data, keyPath);
-  const valueType = getType(value);
 
-  if (PRIMITIVES.has(valueType)) {
-    return title.replace(match, value);
+  if (isPrimitive(value)) {
+    return title.replace(match, String(value));
   }
   return title.replace(match, pretty(value, {maxDepth: 1, min: true}));
 };

packages/jest-get-type/src/__tests__/index.test.ts → packages/jest-get-type/src/__tests__/getType.test.ts

@@ -6,7 +6,7 @@
  *
  */
 
-import getType from '..';
+import getType from '../';
 
 describe('.getType()', () => {
   test('null', () => expect(getType(null)).toBe('null'));

packages/jest-get-type/src/__tests__/isPrimitive.test.ts

@@ -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.
+ *
+ */
+
+import {isPrimitive} from '..';
+
+describe('.isPrimitive()', () => {
+  test.each([null, undefined, 100, 'hello world', true, Symbol.for('a')])(
+    'returns true when given primitive value of: %s',
+    primitive => {
+      expect(isPrimitive(primitive)).toBe(true);
+    },
+  );
+
+  test.each([{}, [], () => {}, /abc/, new Map(), new Set(), new Date()])(
+    'returns false when given non primitive value of: %s',
+    value => {
+      expect(isPrimitive(value)).toBe(false);
+    },
+  );
+});

packages/jest-get-type/src/index.ts

@@ -20,9 +20,18 @@ type ValueType =
   | 'symbol'
   | 'undefined';
 
+const PRIMITIVES = new Set<ValueType>([
+  'string',
+  'number',
+  'boolean',
+  'null',
+  'undefined',
+  'symbol',
+]);
+
 // get the type of a value with handling the edge cases like `typeof []`
 // and `typeof null`
-const getType = (value: unknown): ValueType => {
+function getType(value: unknown): ValueType {
   if (value === undefined) {
     return 'undefined';
   } else if (value === null) {
@@ -55,6 +64,8 @@ const getType = (value: unknown): ValueType => {
   }
 
   throw new Error(`value of unknown type: ${value}`);
-};
+}
+
+getType.isPrimitive = (value: unknown) => PRIMITIVES.has(getType(value));
 
 export = getType;