Javascript if variable is undefined then use another

2018-06-26 05:25:07

This question already has an answer here:

Is there a “null coalescing” operator in JavaScript? 8 answers

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.

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;

Or you can use ternary operator

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

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

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