No constructor for taking the json output format as input

[Tuupertunut]

The toJSON() function returns contents of the cache as an array of objects, with key and value fields. However there is no way to input contents in the same format.

[Truong Hoang Dung]

You can do

LRUMap.prototype.fromJSON = function(cache) {
  return new LRUMap(cache.map(it => {
    return [it.key, it.value]
  }))
}

[Rasmus]

Happy to accept a PR for a function like that.

1. Make it a "static" (non-prototype) function on LRUMap
2. Add a test for it

[Tomer Shvueli]

@rsms created PR #41 to address this issue.