CODEWITHSUNDEEP
javascripttry-catch
wraithie
wraithie

Reputation: 363

try-catch returns variable as undefined

Assuming both tries fail, url returns as undefined and console.log doesn't execute in this case. Is there a problem with my stacking of try-catch clauses, or with the scope of the url variable?

I am using try-catch because in my context url1,2, default may not be available.

getURL = function()
{
   var url;
      try{
        url=data.url1;
      }
      catch(err1)
      {
        try{
          url=data.url2;
        }
        catch(err2)
        {
          console.log("Fetching default url");
          url=data.defaulturl;
        }
      }
      finally
      {
        //do something with url
      }
}

I tried using an if-else-if structure, but it returns error if data.url 1/2/default is unavailable.

if('String' === typeof data.url1)
{
}
else if(check for url 2/default etc.){...}

Upvotes: 0

Views: 5069

Answers (1)

Max Zuber
Max Zuber

Reputation: 1229

My last attempt to reinvent the question... But if all the keys are undefined or URL loadings are unsuccessful, there are NO success at all.

getURL = function() {
  var localData = data || {};
  var keys = ['url1', 'url2', 'defaulturl'];
  var success = false;
  var currentKey;
  while (!success && keys.length > 0) {
    currentKey = keys.shift();
    if (localData.hasOwnProperty(currentKey)
      && 'string' === typeof localData[currentKey]) {
      try {
        url = localData[currentKey];

        // Url loading code may throws an exception,
        // or you can throw it below by hands if needed

        // Emulate loading result...
        if (Math.random() > .5) {
          throw 'Error in ' + localData[currentKey] + ' loading';
        }

        success = true;
      } catch(exception) {
        // Logging or something else here
        console.log(exception.toString());
      }
    }
  }
}

Upvotes: 2

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