Fix rvr parsing with slash separated trend (#106)

Resolves #102

src/command/metar/RunwayCommand.ts

@@ -13,7 +13,7 @@ import { ICommand } from "../metar";
 export class RunwayCommand implements ICommand {
   #genericRegex = /^(R\d{2}\w?\/)/;
   #runwayMaxRangeRegex = /^R(\d{2}\w?)\/(\d{4})V(\d{3,4})([UDN])?(FT)?/;
-  #runwayRegex = /^R(\d{2}\w?)\/([MP])?(\d{4})([UDN])?(FT)?$/;
+  #runwayRegex = /^R(\d{2}\w?)\/([MP])?(\d{4})(?:([UDN])|(FT)(?:\/([UDN]))?)$/;
   #runwayDepositRegex = /^R(\d{2}\w?)\/([/\d])([/\d])(\/\/|\d{2})(\/\/|\d{2})$/;
 
   canParse(input: string): boolean {
@@ -42,7 +42,11 @@ export class RunwayCommand implements ICommand {
       if (!matches) throw new UnexpectedParseError("Should be able to parse");
 
       const indicator = matches[2] ? as(matches[2], ValueIndicator) : undefined;
-      const trend = matches[4] ? as(matches[4], RunwayInfoTrend) : undefined;
+      const trend = (() => {
+        if (matches[6]) return as(matches[6], RunwayInfoTrend);
+        if (matches[4]) return as(matches[4], RunwayInfoTrend);
+      })();
+
       const unit = matches[5]
         ? as(matches[5], RunwayInfoUnit)
         : RunwayInfoUnit.Meters;

tests/command/metar/RunwayCommand.test.ts

@@ -205,4 +205,27 @@ describe("RunwayCommand", () => {
       });
     });
   })();
+
+  (() => {
+    const code = "R36/4000FT/D"; // runway info north america style
+    const metar = { runwaysInfo: [] } as unknown as IMetar;
+
+    describe(code, () => {
+      test("canParse", () => {
+        expect(command.canParse(code)).toBe(true);
+      });
+
+      test("parse", () => {
+        command.execute(metar, code);
+
+        expect(metar.runwaysInfo).toHaveLength(1);
+        expect(metar.runwaysInfo[0]).toEqual({
+          name: "36",
+          minRange: 4000,
+          unit: RunwayInfoUnit.Feet,
+          trend: RunwayInfoTrend.Decreasing,
+        });
+      });
+    });
+  })();
 });

tests/parser/parser.test.ts

@@ -248,6 +248,32 @@ describe("MetarParser", () => {
     expect((metar.runwaysInfo[0] as IRunwayInfoRange).trend).toBe("N");
   });
 
+  test("parses canadian station", () => {
+    const input =
+      "CYWG 172000Z 30015G25KT 3/4SM R36/4000FT/D -SN BLSN BKN008 OVC040 M05/M08 A2992 REFZRA WS RWY36 RMK SF5NS3 SLP134";
+
+    const metar = new MetarParser(en).parse(input);
+
+    expect(metar.station).toBe("CYWG");
+    expect(metar.day).toBe(17);
+    expect(metar.hour).toBe(20);
+    expect(metar.minute).toBe(0);
+    expect(metar.wind).toBeDefined();
+    expect(metar.wind?.speed).toBe(15);
+    expect(metar.wind?.gust).toBe(25);
+    expect(metar.wind?.direction).toBe("WNW");
+    expect(metar.wind?.unit).toBe("KT");
+    expect(metar.visibility).toBeDefined();
+    expect(metar.visibility).toEqual({
+      value: 0.75,
+      unit: DistanceUnit.StatuteMiles,
+    });
+    expect(metar.runwaysInfo).toHaveLength(1);
+    expect(metar.runwaysInfo[0].name).toBe("36");
+    expect((metar.runwaysInfo[0] as IRunwayInfoRange).minRange).toBe(4000);
+    expect((metar.runwaysInfo[0] as IRunwayInfoRange).trend).toBe("D");
+  });
+
   test("parses 'AUTO' as station if no station identifier", () => {
     const input = "AUTO 061950Z 10002KT 9999NDV NCD 01/M00 Q1015 RMK=";