Remove items from one array if not in the second array

Question

I state that I have tried for a long time before writing this post.

For an InDesign script, I\'m working with two array of ListItems. Now I\'m trying to remove the items

Answer 1

Array.prototype.contains =  function ( object )
{
	var i = 0, n = this.length;
	
	for ( i = 0 ; i < n ; i++ )
	{
		if ( this[i] === object )
		{
			return true;
		}
	}
	
	return false;
}

Array.prototype.removeItem = function(value, global) {
	var idx;
	var  n = this.length;
	while ( n-- ) {
		if ( value instanceof RegExp && value.test ( this[n]) 
		|| this[n] === value ) {
			this.splice (n, 1 );
			if ( !global ) return this;
		}
	}
	return this;
};

arr_A = ["a","b","d","f","g"];
arr_B = ["a","c","f","h"];

var item
while ( item = arr_A.pop() ) {
	arr_B.contains ( item ) && arr_B.removeItem ( item  );
}

arr_B;