I have a json file (detailing file extensions and their mime types)

I want to pass a function a file extension e.g. docx, return its associated mime type and to stop further searching through the json file

This is what I have so far but I'm getting undefined for mType in my function

2. var fileExt = "docx";
3. var mimeType = getMimeType(fileExt);
4. 
   
6. function getMimeType(fileExt) {
7. var mType;
8. 
   
9. $.getJSON('json/mimeTypes.json', function(data) {
10. $.each(data,function(key, value) {
11. if(key == fileExt) {
12. mType = value;
13. }
14. });
15. });
16. 
    
17. return mType;
18. }
19. 
    

Thanks in advance