From 6ff5e30996a86c48d19b9c532c190a78024a3e52 Mon Sep 17 00:00:00 2001
From: ellenaua <elenasharovar@gmail.com>
Date: Wed, 16 Oct 2019 11:06:52 +0300
Subject: [PATCH] Added a script which allows to compare two versions to check
 what's changed

---
 scripts/compare-versions.js | 90 +++++++++++++++++++++++++++++++++++++
 1 file changed, 90 insertions(+)
 create mode 100644 scripts/compare-versions.js

diff --git a/scripts/compare-versions.js b/scripts/compare-versions.js
new file mode 100644
index 00000000..786640f3
--- /dev/null
+++ b/scripts/compare-versions.js
@@ -0,0 +1,90 @@
+/* jshint esversion: 6 */
+
+const assert = require('assert');
+
+const FROM_YEAR = 1970;
+const TO_YEAR = 2050;
+
+compareVersions('2019b', 'latest');
+
+function compareVersions(v1, v2, timezones = 'all') {
+
+    /**
+     * Get moment-timezone version v1
+     */
+    const version1 = require("../moment-timezone");
+    version1.tz.load(require(`../data/packed/${v1}.json`));
+
+    /**
+     * Get timezone names and dates from v1
+     */
+    const names1 = version1.tz.names();
+    const dates1 = getFormattedDates(version1, timezones);
+
+    /**
+     * Clear cache
+     */
+    delete require.cache[require.resolve('moment')]
+    delete require.cache[require.resolve('../moment-timezone')]
+
+    /**
+     * Get moment-timezone version v2
+     */
+    var version2 = require("../moment-timezone");
+    version2.tz.load(require(`../data/packed/${v2}.json`));
+
+    /**
+     * Get timezone names and dates from v2
+     */
+    const names2 = version1.tz.names();
+    const dates2 = getFormattedDates(version2, timezones);
+
+    console.log(`Comparing versions ${v1} and ${v2} from ${FROM_YEAR} to ${TO_YEAR}`);
+
+    /**
+     * Compare timezone names
+     */
+    names1.forEach((name1, i) => {
+        if (name1 !== names2[i]) {
+            console.log(`${name1} !== ${names2[i]}`);
+        }
+    });
+
+    /**
+     * Compare dates
+     */
+    dates1.forEach((date1, i) => {
+        if (date1.formatted !== dates2[i].formatted) {
+            console.log(`${date1.zone}: ${date1.date} = ${dates1[i].formatted} in ${v1}, ${dates2[i].formatted} in ${v2}`)
+        }
+    });
+}
+
+/**
+ * Iterates from FROM_YEAR to TO_YEAR
+ * and returns formatted dates for each timezone for each month
+ *
+ * @param momentInstance - instance of moment with timezone
+ * @param timezones = 'all' or array of timezones you want to check
+ * @return {Array}
+ */
+function getFormattedDates (momentInstance, timezones = 'all') {
+    const names = timezones === 'all' ? momentInstance.tz.names() : timezones;
+    const dates = [];
+
+    // ensure that names are equal
+    names.forEach((name, i) => {
+        for (let year = FROM_YEAR; year <= TO_YEAR; year++) {
+            for (let month = 1; month <= 12; month++) {
+                const monthFormatted = month < 10 ? '0' + month : month;
+                dates.push({
+                    zone: name,
+                    date: `${year}-${monthFormatted}-01T00:00:00Z`,
+                    formatted: momentInstance(`${year}-${monthFormatted}-01T00:00:00Z`).tz(name).format()
+                });
+            }
+        }
+    });
+
+    return dates;
+}