Incorrect `containsHoles` implementation

The current containsHoles implementation seems to check for undefined values:

Lines 25 to 32 in 2d96ef5

    
           function containsHoles(arr) { 
        
             for (const ele of arr) { 
        
               if (typeof ele === "undefined") { 
        
                 return true; 
        
               } 
        
             } 
        
             return false; 
        
           }

Holes are something else, though!

[undefined, undefined, undefined] is a packed array that happens to contain undefined values.
Examples of holey arrays are [1,,2], x = [1, 2, 3]; delete x[1], new Array(10), and x = []; x[42] = 1.

You can detect holes by using the in operator, or by using hasOwnProperty.

Thanks a lot for the feedback @mathiasbynens. Nice catch, totally missed it.

Changed the implementation #4

	function containsHoles(arr) {
	for (const ele of arr) {
	if (typeof ele === "undefined") {
	return true;
	}
	}
	return false;
	}