fix: only ISO date strings are parsed to Date objects (#3923)

packages/netlify-cms-core/src/formats/__tests__/yaml.spec.js

@@ -8,11 +8,13 @@ describe('yaml', () => {
 
       const result = yaml.fromFile(stripIndent`
       date: 2020-04-02T16:08:03.327Z
+      dateString: 2020-04-02
       boolean: true
       number: 1
       `);
       expect(result).toEqual({
         date: new Date('2020-04-02T16:08:03.327Z'),
+        dateString: '2020-04-02',
         boolean: true,
         number: 1,
       });
@@ -57,6 +59,31 @@ describe('yaml', () => {
     test('does not fail on closing separator', () => {
       expect(yaml.fromFile('---\n[]\n---')).toEqual([]);
     });
+
+    test('parses single quoted string as string', () => {
+      expect(yaml.fromFile('name: y')).toEqual({ name: 'y' });
+    });
+
+    test('parses ISO date string as date', () => {
+      expect(yaml.fromFile('date: 2020-04-02T16:08:03.327Z')).toEqual({
+        date: new Date('2020-04-02T16:08:03.327Z'),
+      });
+    });
+
+    test('parses partial date string as string', () => {
+      expect(yaml.fromFile('date: 2020-06-12')).toEqual({
+        date: '2020-06-12',
+      });
+      expect(yaml.fromFile('date: 12-06-2012')).toEqual({
+        date: '12-06-2012',
+      });
+    });
+
+    test('parses partial time value as string', () => {
+      expect(yaml.fromFile('time: 10:05')).toEqual({
+        time: '10:05',
+      });
+    });
   });
   describe('toFile', () => {
     test('outputs valid yaml', () => {

packages/netlify-cms-core/src/formats/yaml.js

@@ -17,12 +17,28 @@ const addComments = (items, comments, prefix = '') => {
   });
 };
 
+const timestampTag = {
+  identify: value => value instanceof Date,
+  default: true,
+  tag: '!timestamp',
+  test: RegExp(
+    '^' +
+    '([0-9]{4})-([0-9]{2})-([0-9]{2})' + // YYYY-MM-DD
+    'T' + // T
+    '([0-9]{2}):([0-9]{2}):([0-9]{2}(\\.[0-9]+)?)' + // HH:MM:SS(.ss)?
+    'Z' + // Z
+      '$',
+  ),
+  resolve: str => new Date(str),
+  stringify: value => value.toISOString(),
+};
+
 export default {
   fromFile(content) {
     if (content && content.trim().endsWith('---')) {
       content = content.trim().slice(0, -3);
     }
-    return yaml.parse(content, { version: '1.1' });
+    return yaml.parse(content, { customTags: [timestampTag] });
   },
 
   toFile(data, sortedKeys = [], comments = {}) {