Angular：如何从内循环中脱离外循环？

Question

I tried using break Statement. but didnt worked out. I wanted to break out from outer loop as soon as some condition matches in inner loop.

     angular.forEach(myfilejob, function(fieldMapO) {
                    var count = 0;
                    angular.forEach(myfilejob, function(fieldMapI) {
                        if(fieldMapO.key == fieldMapI.key){
                            $scope.dupKey = fieldMapI.key;
                            count ++;
                        }
                    });

                    if(count>1){
                        $scope.dups = true;
                        // tried break , but didnt work

                    }
                    else{
                        $scope.dups = false;
                    }

                });

Answer 1

When you use forEach , there is no way to pause iteration - not even by using return . If you want a way to stop iteration in the middle of your loop, you must use an actual for or while loop (probably something like for..in or for..of or a traditional three-statement for(var i = 0; i < whatever; i++ loop if myfilejob is an array).

However, once you have done that, you can then label the loops to get the exact effect you're looking for:

outerDupLoop:
for (var outerIndex in myfilejob) {
    var fieldMapO = myfilejob[outerIndex];
    var count = 0;
    innerDupLoop:
    for (var innerIndex in myfilejob) {
        var fieldMapI = myfilejob[innerIndex];
        if(fieldMapO.key == fieldMapI.key){
           $scope.dupKey = fieldMapI.key;
           count ++;
        }
    });

    if(count>1){
        $scope.dups = true;
        break outerDupLoop; // break from the outer loop
    } else {
       $scope.dups = false;
    }
}

(Never mind that the break statement you were trying to add was in the outer loop anyway - removing the labels from this example would make this functionally equivalent. Did you mean to refactor the (count > 1) check so that it would work properly inside the inner loop?)

Answer 2

You can use return, which will essentially break out of the loop. If you want to do it within the inner loop, set a boolean to true, and check for it in the outer loop.

var dupsExist = false;
angular.forEach(myfilejob, function(fieldMapI) {
    if(fieldMapO.key == fieldMapI.key){
        $scope.dupKey = fieldMapI.key;
        dupsExist = true;
        return;
    }
});
if (dupsExist){
    return;
}

Answer 3

I suggest you define a bool when your inner condition is satisfied

angular.forEach(myfilejob, function(fieldMapO) {
                var count = 0;
                var conditionFlag = false;
                angular.forEach(myfilejob, function(fieldMapI) {
                    if(fieldMapO.key == fieldMapI.key){
                        $scope.dupKey = fieldMapI.key;
                        count ++;
                        //condition is fulfilled so boolean is true now
                        conditionFlag = true
                        return false
                    }
                });


                if(count>1){
                    $scope.dups = true;

                }
                else{
                    $scope.dups = false;
                }
                //check if condition is satisfied then exit outer loop too
                if(conditionFlag){
                    return false;
                }
            });

Hope it helps