Add toBeValidDate matcher

Issue: jest-community#117

.all-contributorsrc

@@ -277,7 +277,9 @@
       "avatar_url": "https://avatars2.githubusercontent.com/u/980783?v=4",
       "profile": "http://foss-geek.blogspot.com/",
       "contributions": [
-        "code"
+        "code",
+        "test",
+        "doc"
       ]
     },
     {

README.md

@@ -54,8 +54,10 @@ If you've come here to help contribute - Thanks! Take a look at the [contributin
     - [.toBeBoolean()](#tobeboolean)
     - [.toBeTrue()](#tobetrue)
     - [.toBeFalse()](#tobefalse)
-  - [~~Date~~](#date)
-  - [.toBeDate()](#tobedate)
+  - [Date](#date)
+    - [.toBeDate()](#tobedate)
+    - [.toBeValidDate()](#tobevaliddate)
+    - Further proposals in [#117](https://github.com/jest-community/jest-extended/issues/117) PRs welcome
   - [Function](#function)
     - [.toBeFunction()](#tobefunction)
   - [Mock](#mock)
@@ -333,6 +335,20 @@ test('passes when value is a date', () => {
 });
 ```
 
+### .toBeValidDate()
+
+Use `.toBeValidDate` when checking if a given `Date` object is valid.
+
+```
+test('passes when Date is valid', () => {
+  expect(new Date()).toBeValidDate();
+  expect('01/01/2018').not.toBeValidDate();
+  expect(new Date('01/01/2018').toBeValidDate();
+  expect(new Date('01/90/2018').not.toBeValidDate();
+  expect(undefined).not.toBeValidDate();
+});
+```
+
 ### Function
 
 #### .toBeFunction()

src/matchers/index.js

@@ -44,6 +44,7 @@ import toBeSealed from './toBeSealed';
 import toIncludeRepeated from './toIncludeRepeated';
 import toHaveBeenCalledBefore from './toHaveBeenCalledBefore';
 import toBeDate from './toBeDate';
+import toBeValidDate from './toBeValidDate';
 
 export default [
   toBeEven,
@@ -91,5 +92,6 @@ export default [
   toSatisfy,
   toIncludeRepeated,
   toHaveBeenCalledBefore,
-  toBeDate
+  toBeDate,
+  toBeValidDate
 ].reduce((acc, matcher) => ({ ...acc, ...matcher }), {});

src/matchers/toBeDate/index.test.js

@@ -15,19 +15,12 @@ describe('.toBeDate', () => {
 });
 
 describe('.not.toBeDate', () => {
-  each([
-    [false],
-    [true],
-    [0],
-    [''],
-    [{}],
-    [() => {}],
-    [undefined],
-    [null],
-    [NaN]
-  ]).test('passes when not given a date: %s', given => {
-    expect(given).not.toBeDate();
-  });
+  each([[false], [true], [0], [''], [{}], [() => {}], [undefined], [null], [NaN]]).test(
+    'passes when not given a date: %s',
+    given => {
+      expect(given).not.toBeDate();
+    }
+  );
 
   test('fails when given a date', () => {
     expect(() => expect(new Date('2018-01-01T13:00:00.000Z')).not.toBeDate()).toThrowErrorMatchingSnapshot();

src/matchers/toBeValidDate/__snapshots__/index.test.js.snap

@@ -0,0 +1,17 @@
+// Jest Snapshot v1, https://goo.gl/fbAQLP
+
+exports[`.not.toBeValidDate fails when given a valid date value 1`] = `
+"<dim>expect(</><red>received</><dim>).not.toBeValidDate(</><dim>)</>
+
+Expected value to not be a valid date received:
+  <red>2018-01-01T13:00:00.000Z</>"
+`;
+
+exports[`.toBeValidDate fails when given an invalid date 1`] = `"Invalid time value"`;
+
+exports[`.toBeValidDate fails when not given non-date values 1`] = `
+"<dim>expect(</><red>received</><dim>).toBeValidDate(</><dim>)</>
+
+Expected value to be a valid date received:
+  <red>1</>"
+`;

src/matchers/toBeValidDate/index.js

@@ -0,0 +1,26 @@
+import { matcherHint, printReceived } from 'jest-matcher-utils';
+
+import predicate from './predicate';
+
+const passMessage = received => () =>
+  matcherHint('.not.toBeValidDate', 'received', '') +
+  '\n\n' +
+  'Expected value to not be a valid date received:\n' +
+  `  ${printReceived(received)}`;
+
+const failMessage = received => () =>
+  matcherHint('.toBeValidDate', 'received', '') +
+  '\n\n' +
+  'Expected value to be a valid date received:\n' +
+  `  ${printReceived(received)}`;
+
+export default {
+  toBeValidDate: expected => {
+    const pass = predicate(expected);
+    if (pass) {
+      return { pass: true, message: passMessage(expected) };
+    }
+
+    return { pass: false, message: failMessage(expected) };
+  }
+};

src/matchers/toBeValidDate/index.test.js

@@ -0,0 +1,41 @@
+import each from 'jest-each';
+
+import matcher from './';
+
+expect.extend(matcher);
+
+describe('.toBeValidDate', () => {
+  test('passes when given a valid date', () => {
+    expect(new Date()).toBeValidDate();
+  });
+
+  test('fails when given an invalid date', () => {
+    expect(() => expect(new Date('2018-90-90T13:00:00.000Z')).toBeValidDate()).toThrowErrorMatchingSnapshot();
+  });
+
+  test('fails when not given non-date values', () => {
+    expect(() => expect(1).toBeValidDate()).toThrowErrorMatchingSnapshot();
+  });
+});
+
+describe('.not.toBeValidDate', () => {
+  each([
+    [new Date('01/90/2018')],
+    [new Date('32/01/2018')],
+    [false],
+    [true],
+    [0],
+    [''],
+    [{}],
+    [() => {}],
+    [undefined],
+    [null],
+    [NaN]
+  ]).test('passes when not given a date: %s', given => {
+    expect(given).not.toBeValidDate();
+  });
+
+  test('fails when given a valid date value', () => {
+    expect(() => expect(new Date('2018-01-01T13:00:00.000Z')).not.toBeValidDate()).toThrowErrorMatchingSnapshot();
+  });
+});

src/matchers/toBeValidDate/predicate.js

@@ -0,0 +1,7 @@
+let is = type => value => Object.prototype.toString.call(value) === `[object ${type}]`;
+
+let hasDateType = is('Date');
+
+let isValidDate = value => hasDateType(value) && !isNaN(value) && !isNaN(value.getTime());
+
+export default expected => isValidDate(expected);

src/matchers/toBeValidDate/predicate.test.js

@@ -0,0 +1,24 @@
+import each from 'jest-each';
+import predicate from './predicate';
+
+describe('toBeDate Predicate', () => {
+  test('returns true when given a valid date', () => {
+    expect(predicate(new Date('12/25/2017'))).toBe(true);
+  });
+
+  each([
+    [new Date('01/90/2018')],
+    [new Date('32/01/2018')],
+    [true],
+    [false],
+    [''],
+    [0],
+    [{}],
+    [() => {}],
+    [undefined],
+    [null],
+    [NaN]
+  ]).test('returns false when given: %s', given => {
+    expect(predicate(given)).toBe(false);
+  });
+});

types/index.d.ts

@@ -86,10 +86,15 @@ declare namespace jest {
     toBeFalse(): R;
 
     /**
-     * Use .toBeDate when checking if a value is a Date.
+     * Use `.toBeDate` when checking if a value is a `Date`.
      */
     toBeDate(): R;
 
+    /**
+     * Use `.toBeValidDate` when checking if a value is a `valid Date`.
+     */
+    toBeValidDate(): R;
+
     /**
      * Use `.toBeFunction` when checking if a value is a `Function`.
      */
@@ -301,4 +306,3 @@ declare namespace jest {
     toIncludeMultiple(substring: string[]): R;
   }
 }
-