Fix pretty format failing when printing invalid dates (#6635)

* Fix pretty format failing when printing invalid dates * Updates changelog * fixes wrong update of changelog * changes the way pretty format outputs invalid dates
jestjs · Aug 15, 2018 · 5d65701 · 5d65701
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diff --git a/CHANGELOG.md b/CHANGELOG.md
@@ -62,6 +62,10 @@
 
 - `[jest-haste-map]` Optimize watchman crawler by using `glob` on initial query ([#6689](https://github.com/facebook/jest/pull/6689))
 
+### Fixes
+
+- `[pretty-format]` Fix formatting of invalid Date objects ([#6635](https://github.com/facebook/jest/pull/6635))
+
 ## 23.4.0
 
 ### Features

diff --git a/packages/pretty-format/src/__tests__/pretty_format.test.js b/packages/pretty-format/src/__tests__/pretty_format.test.js
@@ -234,6 +234,11 @@ describe('prettyFormat()', () => {
     expect(prettyFormat(val)).toEqual('2001-09-09T01:46:40.000Z');
   });
 
+  it('prints an invalid date', () => {
+    const val = new Date(Infinity);
+    expect(prettyFormat(val)).toEqual('Date { NaN }');
+  });
+
   it('prints an empty object', () => {
     const val = {};
     expect(prettyFormat(val)).toEqual('Object {}');

diff --git a/packages/pretty-format/src/index.js b/packages/pretty-format/src/index.js
@@ -146,7 +146,7 @@ function printBasicValue(
     return printSymbol(val);
   }
   if (toStringed === '[object Date]') {
-    return toISOString.call(val);
+    return isNaN(+val) ? 'Date { NaN }' : toISOString.call(val);
   }
   if (toStringed === '[object Error]') {
     return printError(val);