迭代 JSON 文件并且没有在 Javascript 中正确返回结果

Question

I have a JSON file and iterating it. If there is a column called "validation" : {"required"} then I add a count in a variable like below:

for (var a= 0; a<66; ++a) {
        var requiredFieldsInPart = 0;

            for (var b=0; b<$scope.groups[a].sections[0].fields.length; ++b) {
             try {
                 throw console.log($scope.groups[a].sections[0].fields[b]["validations"]["required"]);
             }
             catch (e) {
                 console.log(e);
             }
             requiredFieldsInPart += 1;
         }

The reason I'm using try/catch is because I wanna pass if there is an error. There are some objects which do not have "validations" attribute so it was causing an error.

Let's say there are total 21 fields in a section and 19 of them have "validations" and 2 do not have "validations" . So requiredFieldsInPart should return 19. However, it returns 21 right now. How do I make sure it only counts an object with "validations" ??

Answer 1

I would proceed by filtering the source array and returning the size of the result :

return $scope.groups.filter(group =>
                             group.sections[0].fields[b].validations && 
                             group.sections[0].fields[b].validations.required
                           ).length

Answer 2

for (var a= 0; a<66; ++a) {
    var requiredFieldsInPart = 0;

        for (var b=0; b<$scope.groups[a].sections[0].fields.length; ++b) {
         try {
             console.log($scope.groups[a].sections[0].fields[b]["validations"]["required"]);
             requiredFieldsInPart += 1;//put this line inside 'try' block will do
         } catch (e) {
             console.log(e);
         }             
         }
}