Delete from array in javascript

Question

3 hours ago, I asked a question in SO , about deleting a part of an object, so I linked this question to it:

delete a part of object in javascript

but now an

Answer 1

Walk through the array in reverse order, and use .splice to remove the element.
You have to walk in the reverse order, because otherwise you end up skipping elements ^{See below}.

for (var i = Roomdata.length-1; i >= 0; i--) {
    if (Roomdata[i].id == X) {
        Roomdata.splice(i, 1);
        break;
    }
}

What happens if you don't walk in the reverse order:

// This happens in a for(;;) loop:
// Variable init:
var array = [1, 2, 3];
var i = 0;

array.splice(i, 1); // array = [2, 3]   array.length = 2
// i < 2, so continue
i++;  // i = 1    

array.splice(i, 1); // i=1, so removes item at place 1: array = [2]
// i < 1 is false, so stop.

// array = [2]. You have skipped one element.