Rework toDate and extract parseISO

CHANGELOG.md

@@ -748,6 +748,9 @@ for the list of changes made since `v2.0.0-alpha.1`.
 
 - [Fixed DST issue](https://github.com/date-fns/date-fns/pull/1003). See [#972](https://github.com/date-fns/date-fns/issues/972) and [#992](https://github.com/date-fns/date-fns/issues/992) for more details.
 
+- Fixed DST issue in `eachDayOfInterval` that caused time in the days
+  after DST change to have the shift as well.
+
 - Fix bug in Galician locale caused by incorrect usage of `getHours`
   instead of `getUTCHours`.
 

scripts/test/dst.sh

@@ -10,3 +10,4 @@ export PATH="$(yarn bin):$PATH"
 
 env TZ=America/Sao_Paulo babel-node ./test/dst/parseISO/basic.js
 env TZ=Pacific/Apia babel-node ./test/dst/parseISO/samoa.js
+env TZ=Asia/Damascus babel-node ./test/dst/eachDayOfInterval/basic.js

test/dst/eachDayOfInterval/basic.js

@@ -0,0 +1,22 @@
+// This is basic DST test for eachDayOfInterval
+
+import eachDayOfInterval from '../../../src/eachDayOfInterval'
+import assert from 'assert'
+
+if (process.env.TZ !== 'Asia/Damascus')
+  throw new Error('The test must be run with TZ=Asia/Damascus')
+
+if (parseInt(process.version.match(/^v(\d+)\./)[1]) < 10)
+  throw new Error('The test must be run on Node.js version >= 10')
+
+assert.deepEqual(
+  eachDayOfInterval({
+    start: new Date(2020, 2, 26),
+    end: new Date(2020, 2, 28)
+  }).map(d => d.toString()),
+  [
+    'Thu Mar 26 2020 00:00:00 GMT+0200 (Eastern European Standard Time)',
+    'Fri Mar 27 2020 01:00:00 GMT+0300 (Eastern European Summer Time)',
+    'Sat Mar 28 2020 00:00:00 GMT+0300 (Eastern European Summer Time)'
+  ]
+)