Add more error checking in getNightlyFileName (#237)

Author: DilumAluthge

lib/installer.js

@@ -124,22 +124,34 @@ function getNightlyFileName(arch: string): string {
     [fileExt1, , ] = getDesiredFileExts()
 
     if (osPlat == 'win32') {
-        versionExt = arch == 'x64' ? '-win64' : '-win32'
+        if (arch == 'x86') {
+            versionExt = '-win32'
+        } else if (arch == 'aarch64') {
+            throw new Error('Aarch64 Julia is not available on Windows')
+        } else if (arch == 'x64') {
+            versionExt = '-win64'
+        } else {
+            throw new Error(`Architecture ${arch} is not supported on Windows`)
+        }
     } else if (osPlat == 'darwin') {
         if (arch == 'x86') {
-            throw new Error('32-bit Julia is not available on macOS')
+            throw new Error('32-bit (x86) Julia is not available on macOS')
         } else if (arch == 'aarch64') {
             versionExt = '-macaarch64'
-        } else {
+        } else if (arch == 'x64') {
             versionExt = '-mac64'
+        } else {
+            throw new Error(`Architecture ${arch} is not supported on macOS`)
         }
     } else if (osPlat === 'linux') {
         if (arch == 'x86') {
             versionExt = '-linux32'
         } else if (arch == 'aarch64') {
             versionExt = '-linux-aarch64'
-        } else {
+        } else if (arch == 'x64') {
             versionExt = '-linux64'
+        } else {
+            throw new Error(`Architecture ${arch} is not supported on Linux`)
         }
     } else {
         throw new Error(`Platform ${osPlat} is not supported`)