IndexedMap

A map that maintains the order of entries. Give access to entries by index or key. Keys have to be unique in map.

Stability: 1 Experimental

(Stability Index: http://nodejs.org/api/documentation.html#documentation_stability_index)

Install

npm install indexed-map --production

Usage

var IndexedMap = require('indexed-map')
var myMap = IndexedMap();
// add an entry
myMap.insert('myKey', { myProperty:'My Value' });

Keys have to be of type 'string', values can by any type, there is no restrictions.

Constructor

• var myMap = IndexedMap();
• var myMap = new IndexedMap();

Keyword new is optional, it will be called by IndexedMap itself, if necessary.

properties

• length {number} the count of entries

• keys {Array} keys in the current order

  That is not a clone, it is the real keys array of the indexedMap. So do not add, change or remove elements. That would result in an inconsistent state of indexedMap itself.

  The advantage of not cloning the key map is, that you can easily manipulat the order of keys, if you like. So you could use the reverse or sort method of Array.

key based methods:

• insert( key:string, value:any ):value|null

  Insert new element before the referenced element targetKey. If reference is null or not found, new element is inserted at the end of the list. If key always used in the map, null will be returned.

• set( key:string, value:any )oldValue|null

  Overwrite the value for the given key. return old value or null, if key not found.

• move( key:string, targetKey:string )value|null

• remove( key:string ):oldValue|null

• has( key:string ):boolean

• get( key:string ):value|null

• nextOf( key:string ):key|null

• prevOf( key:string ):key|null

index based equivalent with sufix 'At':

• getAt( index:number ):value|null
• setAt( index:number, value:any ):oldValue|null
• insertAt( index:number, value:any ):value|null
• moveAt( index:number, targetIndex:number ):value|null
• removeAt( index:number ):oldValue|null

first, last, previous, next:

• getFirst():value|null
• getLast():value|null
• getPrevOf( key:string ):value|null
• getNextOf( key:string ):value|null

iterating methods

• sort(callback) sort the map, that method manipulate the indexedMap. This function is analog to the sort function of Array. if no callback is specified, keys will be sorted lexicographically

  params callback {function(valueA, valueB ):number } - optional

  • called in context of indexedMap
  • compareFunction have to return 0 for equal, <0 for a < b or >0 for a > b

• find(callback) return the first key, where callback(key, value) returned true.

  param callback {function(key:string, value:object):boolean} - required

  • called for every entry in context of indexedMap. return true will stop the search and return the value of current entry.

  param startIndex {number} - optional position to start the search, default: 0

  returns value or null

• each(callback) Visit every entry in the indexedMap. Start at given startIndex. Run until end or the given callback returns 'false'.

  param callback {function(key:string, value:object):boolean} - required

  • called for every entry in context of current IndexedMap.
  • stop loop from within the callback function by returning false.

  param startIndex {number} - optional position to start the run, default: 0

  returns null

Test

cd <IndexedMapDir>
npm install .
npm test

License

The MIT License

Copyright (c) 2012 Tobias Lindig

Permission is hereby granted, free of charge, to any person obtaining a copy of this software and associated documentation files (the 'Software'), to deal in the Software without restriction, including without limitation the rights to use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the Software, and to permit persons to whom the Software is furnished to do so, subject to the following conditions:

The above copyright notice and this permission notice shall be included in all copies or substantial portions of the Software.

THE SOFTWARE IS PROVIDED 'AS IS', WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.