monitorService.getFMCMonitor({ scenario: 'indoor'},function(res){
$scope.data = res;
});
//$scope.$watch('data',(n,o)=>console.log(n));
console.log($scope.data); ==> undefined
monitorService is a service that obtains background data. If $watch is not used, how to synchronize the value of $timeout with $scope.data? Just print $scope.data, which is the value obtained from the service, not undefined
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Because it is asynchronous, the ajax request does not return when you print, so it is naturally undefined.
You can do this, pass a callback as a parameter, or a promise, both are fine.