Javascript if variable is undefined then use another

Question

I have two scopes $scope.job and $scope.jobs

I have var job;

If $scope.job is undefined I would like $scope.jobs to work under job so it would be var job = $scope.jobs but if $scope.job is defined I want to write it to that variable too.

if ( $scope.job ) {
    var job = $scope.job; 
} else {
    var job = $scope.jobs; 
}

But in shorthand

*"I want to write it to that variable too."* -- As in you want to write to *both* variables? Currently you are writing to one. — Casey Falk, Aug 12 '14 at 12:15

score 1 · Accepted Answer · edited Aug 12 '14 at 12:21

1

I want to leave short comment but now I understand that will be better if I explain.

var job = $scope.job || $scope.jobs;

undefined == false; // prints true

So that's how it works.

If $scope.job == undefined == false || $scope.jobs == {...} == true.

If job will be undefined - it will be false so or operand returns true value.

edited Aug 12 '14 at 12:21

ivarni

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answered Aug 12 '14 at 12:17

Eugene Obrezkov

2,910
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score 0 · Answer 2 · answered Aug 12 '14 at 12:19

0

So if i understand what you mean:

if ($scope.job)
  var job = $scope.job;
else
{
  var job = $scope.jobs;
  $scope.job = $scope.jobs;
}

well, shorthand then:

var job = $scope.job = $scope.job || $scope.jobs;

answered Aug 12 '14 at 12:19

DoXicK

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score 0 · Answer 3 · answered Aug 12 '14 at 12:24

0

Or you can use ternary operator

var job = $scope.job ? $scope.job : $scope.jobs

or

var job = $scope.job == undefined ? $scope.job : $scope.jobs

answered Aug 12 '14 at 12:24

Mike S.

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Javascript if variable is undefined then use another

3 Answers3