"move to top" behavior uses slice, should use splice

[aduth]

At this line, I expect you are intending to use Array#splice, not Array#slice:

lru-memoize/src/lruCache.js

Line 13 in 86f655e

entries.slice(cacheIndex, 1)

Splice is mutative and as used would result in the item being removed at the given index. Slice is non-mutative and as used does nothing (aside from wasting cycles to create a copy of the array starting at index 1), therefore the cache entry will exist twice in the entries set (since it is not removed, then later prepended to the set).

[jimmytuc]

Related #88