fixes issue in prepare script

src/scripts/prepare.js

@@ -1,18 +1,39 @@
 const { exec } = require('child_process');
 const semver = require('semver');
 
+function getTnsVersion() {
+
+    try {
+        return semver.major(stdout);
+    } catch(error) {
+        try {
+            const regex = /(^\d\.\d\.\d$)/gm;
+            const match = regex.exec(stdout);
+
+            if (match && match[0]) {
+                return semver.major(match[0]);
+            }
+        } catch(error) {
+            // noop
+        }
+    }
+
+    console.warn('Could not get Nativescript version from nativescript cli. Assuming version 7+');
+    return 7;
+}
+
 exec('tns --version', (err, stdout, stderr) => {
     if (err) {
         // node couldn't execute the command
         console.log(`tns --version err: ${err}`);
         return;
     }
 
-    const tnsVersion = semver.major(stdout);
+    const tnsVersion = getTnsVersion();
 
     // execute 'tns plugin build' for {N} version > 4. This command builds .aar in platforms/android folder.
     if (tnsVersion >= 4) {
         console.log(`executing 'tns plugin build'`);
         exec('tns plugin build');
     }
-}); 
+});