// Copyright 2019 the V8 project authors. All rights reserved.// Use of this source code is governed by a BSD-style license that can be// found in the LICENSE file.letdf=newIntl.DateTimeFormat("en");// A modern dateletd1=newDate(2019,3,4);letd2=newDate(2019,4,5);assertEquals(df.format(d1),df.formatRange(d1,d1));assertEquals(df.format(d2),df.formatRange(d2,d2));assertEquals("4/4/2019 – 5/5/2019",df.formatRange(d1,d2));// An old date just before the Julian / Gregorian switchletd3=newDate(1582,8,13);letd4=newDate(1582,9,14);assertEquals(df.format(d3),df.formatRange(d3,d3));assertEquals(df.format(d4),df.formatRange(d4,d4));assertEquals("9/13/1582 – 10/14/1582",df.formatRange(d3,d4));// An older dateletd5=newDate(1000,0,1);letd6=newDate(1001,1,2);assertEquals(df.format(d5),df.formatRange(d5,d5));assertEquals(df.format(d6),df.formatRange(d6,d6));assertEquals("1/1/1000 – 2/2/1001",df.formatRange(d5,d6));