map array of methods

map method will loop through the array of arrays, each array to be processed in a function, and returns a function after treatment; but if we change the array itself in a function, then what will happen?

       var removeElement = function(nums, val) {
            nums.map(function (item, index){
                if(item === val){
                    console.log(index); // 2 3
                    nums.splice(index, 1);
                }
            });
        };
        removeElement([1,2,3,4,3,5], 3);

As can be seen by the above example, if we change the original array in one cycle of a case, then the next processing cycle is carried out on the basis of the array has changed.

        var removeElement = function (the nums, Val) { 
            nums.map ( function (Item, index) {
                 IF (Item === Val) { 
                    nums.splice (index, . 1); // deleted index entry array 2 , and after a 2 becomes item 2 of the index, but the index has been treated 2, so 2 this index is no treatment, leading to a 2 is not removed. 
                } 
            }); 
        }; 
        removeElement ([ 0, 1,2,2,3,0,4,2], 2);

If the above code is an array: [0,1,2,2,2,3,0,4,2], nums [0, 1, 2, 3, 0, 4]; if [0, 1,2,2,2,2,3,0,4,2], nums [0, 1, 2, 2, 3, 0, 4]