Question

I am attempting to populate array:

var array2 = ["a", "b", "c"];

With some random number/value, so that the value separates each original value.
However, using a for loop like this:

for (var am = 1; am < array2.length; am+2) {
   array2.splice(am, 0, undefined);
}

Causes my browser to freeze, since on each splice the array2’s length mutates and causes an infinite loop so I attempted this method:

var l = array2.length;

for(var i = 1; i < l; i+2) {
   array2.splice(i, 0, undefined);
}

Now I don’t know what’s going on. I assume l is mutating again.

I have to advance i for two because array2 after the first splice becomes:

["a", undefined, "b", "c"];

However, since i = 3 and I’ve set the expression i < l, the only explanation is that l is changing again.

Any explanation would be welcome. The end result of how I want the code to proceed is:

array2 = ["a", undefined, "b", undefined, "c"];

Answer 1

for (var am = 1; am < array2.length; am+2) {

You’re not actually incrementing am in that line. Change it to:

for (var am = 1; am < array2.length; am+=2) {

Using += means am = am + 2