Added by Johan above

implemented for JS. Java could do with that as well; the instructions are very clear about returning a new array.

added. apologies for the delay. :P

Vulnerability for input mutation fixed.
Test for input mutation added.

Because the goal of our function is to implement "one swipe"(if this explanation makes the goal clearer):

A given tile can only merge once. (this limits any tile to be summed/combined only 1 time)

Your solution is mutating the input array and as a consequence, the tests are misbehaving. It is indeed a kata issue because the tests should not be vulnerable to this, but at the same time your solution is not exactly correct:

This function takes the array line as a parameter and returns a new array with the tile values from line slid towards the front of the array (index 0) and merged.

Why isn't [2,0,2,4] == [8,0,0,0]?

Really tricky and puzzling kata to solve I'd say, compliments, I had a lot of fun with it.

Your kata was.... Unexplainably low for 6 kyu.
Good Job on making me cry solving this :)

This Kata had me hooked on the game for a while. :-D
Damn. Never reached 2048. I gave up crying.

so hard for 6kyu, but so interesting

Approved.

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