Persistent ordered mapping from strings
npm install orderedmapPersistent data structure representing an ordered mapping from strings
to values, with some convenient update methods.
This is not an efficient data structure for large maps, just a minimal
helper for cleanly creating and managing small maps in a way that
makes their key order explicit and easy to think about.
License: MIT
The exported value from this module is the class OrderedMap,
instances of which represent a mapping from strings to arbitrary
values.
OrderedMap.from(value: ?Object | OrderedMap) → OrderedMap
Return a map with the given content. If null, create an empty map. If
given an ordered map, return that map itself. If given an object,
create a map from the object's properties.
Instances of OrderedMap have the following methods and properties:
get(key: string) → ?any
Retrieve the value stored under key, or return undefined when
no such key exists.
update(key: string, value: any, newKey: ?string) → OrderedMap
Create a new map by replacing the value of key with a new
value, or adding a binding to the end of the map. If newKey is
given, the key of the binding will be replaced with that key.
remove(key: string) → OrderedMap
Return a map with the given key removed, if it existed.
addToStart(key: string, value: any) → OrderedMap
Add a new key to the start of the map.
addToEnd(key: string, value: any) → OrderedMap
Add a new key to the end of the map.
addBefore(place: string, key: value: string, value: any) → OrderedMap
Add a key after the given key. If place is not found, the new
key is added to the end.
forEach(f: (key: string, value: any))
Call the given function for each key/value pair in the map, in
order.
prepend(map: Object | OrderedMap) → OrderedMap
Create a new map by prepending the keys in this map that don't
appear in map before the keys in map.
append(map: Object | OrderedMap) → OrderedMap
Create a new map by appending the keys in this map that don't
appear in map after the keys in map.
subtract(map: Object | OrderedMap) → OrderedMap
Create a map containing all the keys in this map that don't
appear in map.
toObject() -> Object
Return an object that has the same key/value pairs as the map.
size: number
The amount of keys in this map.