Cannot read property 'chrome' of undefined

Question

What is causing it and how to avoid it? I cannot catch the exception.
The first time chooseEntry is cancelled createWriter throws an exception sometimes, I can catch this one:

Error in response to fileSystem.chooseEntry: TypeError: Cannot call method 'createWriter' of undefined

then when I try to call chooseEntry again this exception is thrown:

try{
    chrome.fileSystem.chooseEntry({ type:'saveFile',suggestedName:$("#mydiv").text()+".jpg",accepts:[{ extensions:['jpg'] }] },function(fileEntry){
        try{
            fileEntry.createWriter(function(writer) {
                writer.onerror = errorHandler;
                writer.onwriteend = function(e) { console.log('write complete'); };
                writer.write(data); //data is a blob
            });
        }catch(err){ console.log("error",err.message); }
    });
}catch(err){ console.log("error",err.message); }

> Error in response to fileSystem.chooseEntry: TypeError: Cannot read property 'chrome' of undefined

Answer 1

To avoid first exception check the fileEntry for undefined,

       try{
          if(fileEntry) { 
              fileEntry.createWriter(function(writer) {
                writer.onerror = errorHandler;
                writer.onwriteend = function(e) { console.log('write complete'); };
                writer.write(data); //data is a blob
             });
           }
        }catch(err){ console.log("error",err.message); }