Fix parsing of "calm wind" (#81)

* fix: correctly parse calm wind

* test: ensure correct wind unit is parsed

* test: ensure visibility is not mistaken for wind speed

* style: apply formatting

src/command/common.ts

@@ -98,7 +98,7 @@ export class MainVisibilityCommand implements ICommand {
 }
 
 export class WindCommand implements ICommand {
-  #regex = /^(VRB|00|[0-3]\d{2})(\d{2})G?(\d{2,3})?(KT|MPS|KM\/H)?/;
+  #regex = /^(VRB|000|[0-3]\d{2})(\d{2})G?(\d{2,3})?(KT|MPS|KM\/H)?/;
 
   canParse(windString: string): boolean {
     return this.#regex.test(windString);

tests/parser/parser.test.ts

@@ -386,7 +386,7 @@ describe("MetarParser", () => {
 
   test("wind of 0000KT should not parse as minVisibility", () => {
     const metar = new MetarParser(en).parse(
-      "KATW 022045Z 0000KT 10SM SCT120 00/M08 A2996"
+      "KATW 022045Z 00000KT 10SM SCT120 00/M08 A2996"
     );
 
     expect(metar.wind).toStrictEqual({
@@ -400,6 +400,32 @@ describe("MetarParser", () => {
     expect(metar.visibility?.min).toBeUndefined();
   });
 
+  test("wind of 00000MPS should parse with correct unit", () => {
+    const metar = new MetarParser(en).parse("KATL 270200Z 00000MPS");
+
+    expect(metar.wind).toStrictEqual({
+      degrees: 0,
+      speed: 0,
+      unit: "MPS",
+      gust: undefined,
+      direction: "N",
+    });
+  });
+
+  test("visibility should not parse as wind speed", () => {
+    const metar = new MetarParser(en).parse("VIDP 270200Z 00000MPS 0050");
+
+    expect(metar.wind).toStrictEqual({
+      degrees: 0,
+      speed: 0,
+      unit: "MPS",
+      gust: undefined,
+      direction: "N",
+    });
+
+    expect(metar.visibility).toStrictEqual({ unit: "m", value: 50 });
+  });
+
   test("wind variation", () => {
     const metar = new MetarParser(en).parse("LFPG 161430Z 24015G25KT 180V300");