When a function reference is utilized, Coffeescript presents an unusual conversion of the try/catch/finally block

Question

When a function reference is utilized, Coffeescript presents an unusual conversion of the try/catch/finally block

I recently wrote a helper function to handle errors, and I'm attempting to pass it as an argument to the catch function within a promise:

  fetchRecords().then (found) ->
    $scope.recprds = found;
  .catch( Session.handleError )
  .finally( -> $scope.querying = false )

When this code is translated into JavaScript, it looks like this:

  fetchRecords().then(function(found) {
    return $scope.records = found;
  })["catch"](Session.handleError)["finally"](function() {
    return $scope.querying = false;
  });

The issue arises because finally is not a property of my Session.handleError function, causing a JavaScript error.

Is there a different syntax that would be more appropriate in this scenario?

Experiment with it on coffeescript.org

javascript angularjs coffeescript promise

Answer 1

Answer №1

In order to clean up your code, it's important to remove unnecessary semicolons and parentheses.

Reserved words like try, catch, and finally should be used as shown in the example on coffeescript.org:

try
  allHellBreaksLoose()
  catsAndDogsLivingTogether()
catch error
  print error
finally
  cleanUp()

To ensure that chaining works correctly in Coffeescript, consider renaming your helper functions:

fetchRecords().then (found) ->
    $scope.recprds = found
  .helpercatch Session.handleError 
  .helperfinally -> $scope.querying = false

When parsed, your code should look like this:

fetchRecords().then(function(found) {
  return $scope.recprds = found;
}).helpercatch(Session.handleError).helperfinally(function() {
  return $scope.querying = false;
});

Answer 2

In order to clean up your code, it's important to remove unnecessary semicolons and parentheses.

Reserved words like try, catch, and finally should be used as shown in the example on coffeescript.org:

try
  allHellBreaksLoose()
  catsAndDogsLivingTogether()
catch error
  print error
finally
  cleanUp()

To ensure that chaining works correctly in Coffeescript, consider renaming your helper functions:

fetchRecords().then (found) ->
    $scope.recprds = found
  .helpercatch Session.handleError 
  .helperfinally -> $scope.querying = false

When parsed, your code should look like this:

fetchRecords().then(function(found) {
  return $scope.recprds = found;
}).helpercatch(Session.handleError).helperfinally(function() {
  return $scope.querying = false;
});

When a function reference is utilized, Coffeescript presents an unusual conversion of the try/catch/finally block

Answer №1

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