Javascript 时区B将gmt#U偏移量转换为+；5:30格式？

这是我的链接：

正如你所看到的，它将时间相关的数据作为一个大数字，我如何将其转换为“utc+5:30”小时格式…
感谢您除以3600（一小时内的秒数）以小时为单位获得UTC偏移

除以3600（一小时内的秒数）以小时为单位获得UTC偏移

 timezone.csv
 Fields: "zone_id","abbreviation","time_start","gmt_offset","dst"


"370","CDT","-273686400","-18000","1"    
"370","EST","-266432400","-18000","0"
"370","EDT","-52938000","-14400","1"    
"370","EST","-37216800","-18000","0"
"370","EDT","-21488400","-14400","1"
"370","EST","-5767200","-18000","0"
"370","EDT","9961200","-14400","1"
"370","EST","25682400","-18000","0"
"370","EDT","41410800","-14400","1"
"370","EST","57736800","-18000","0"