Maps a timezone abbreviation that a human would type (or that a web page would print next to a
time) to the IANA timezone it most likely means.
Both halves of a region's pair map to the same zone: EST and EDT both give
America/New_York. The abbreviation says which region, the timestamp says which offset. Mapping
EST to a fixed -5 zone instead would turn a July time labeled EST by a site that never
bothers to write EDT into an hour-off reading.
Abbreviations are not unique across the world and IANA never promised they would be, so each
collision here is resolved toward the most populous region that uses it: CST is US Central and
not China or Cuba, IST is India and not Ireland or Israel, AST is Atlantic and not Arabia,
GST is the Gulf and not Chamorro, AMT is the Amazon and not Armenia. Pass a real IANA name
instead when you need one of the others.
EAST, GET, NRT, and WST are real abbreviations that are also ordinary words or airport
codes. Don't feed arbitrary scraped text through getTimezoneFromAbbreviation expecting
those four to miss.
AMST, BRST, EGST, MSD, and PYST name zones that have since abolished the daylight
saving they refer to, but people still type them, so they map to the zone anyway.
Maps a timezone abbreviation that a human would type (or that a web page would print next to a time) to the IANA timezone it most likely means.
Both halves of a region's pair map to the same zone:
ESTandEDTboth giveAmerica/New_York. The abbreviation says which region, the timestamp says which offset. MappingESTto a fixed -5 zone instead would turn a July time labeledESTby a site that never bothers to writeEDTinto an hour-off reading.Abbreviations are not unique across the world and IANA never promised they would be, so each collision here is resolved toward the most populous region that uses it:
CSTis US Central and not China or Cuba,ISTis India and not Ireland or Israel,ASTis Atlantic and not Arabia,GSTis the Gulf and not Chamorro,AMTis the Amazon and not Armenia. Pass a real IANA name instead when you need one of the others.EAST,GET,NRT, andWSTare real abbreviations that are also ordinary words or airport codes. Don't feed arbitrary scraped text through getTimezoneFromAbbreviation expecting those four to miss.AMST,BRST,EGST,MSD, andPYSTname zones that have since abolished the daylight saving they refer to, but people still type them, so they map to the zone anyway.