dictionary.js

  1. /**
  2.  * Dictionary function constructor.
  3.  * 
  4.  * @example const Dictionary = require('dstructures').Dictionary;
  5.  * const myDictionary = new Dictionary();
  6.  * @description In computer science, an associative array, map, symbol table, or 
  7.  * dictionary is an abstract data type composed of a collection of (key, value) pairs, 
  8.  * such that each possible key appears at most once in the collection. Full wikipedia article at:
  9.  * {@link https://en.wikipedia.org/wiki/Associative_array}
  10.  * @public
  11.  * @constructor
  12.  */
  13. class Dictionary {
  15.   constructor(){
  16.     let container = [];
  17.     this.setContainer = (value) => container = value;
  18.     this.getContainer = () => container;
  19.   }
  21.   /**
  22.    * Adds key value pair in a dictionary.
  23.    * 
  24.    * @param {any} key Given key.
  25.    * @param {any} value Given value.
  26.    * @example Dictionary.add('dog', 1); // ['dog': 1]
  27.    * Dictionary.add('dog', 2); // ['dog': 2]
  28.    * Dictionary.add('cat', 1); // ['dog': 2, 'cat': 1]
  29.    */
  30.   add (key, value) {
  31.     if (key === undefined || key === null) {
  32.       return false;
  33.     }
  34.     if (value === undefined || value === null) {
  35.       return false;
  36.     }
  37.     this.getContainer()[key] = value;
  38.   }
  40.   /**
  41.    * Returns the value for the given key.
  42.    * 
  43.    * @param {any} key Given key.
  44.    * @returns Returns the value for the given key.
  45.    * @example Dictionary.add('dog', 1); // ['dog': 1]
  46.    * Dictionary.find('dog'); // 1
  47.    * Dictionary.add('cat', 3); // ['dog': 1, 'cat': 3]
  48.    * Dictionary.find('cat'); // 3
  49.    */
  50.   find (key) {
  51.     return this.getContainer()[key];
  52.   }
  54.   /**
  55.    * Removes the value associated to the given key.
  56.    * 
  57.    * @param {any} key Given key.
  58.    * @example Dictionary.add('dog', 2); // ['dog': 2]
  59.    * Dictionary.add('cat', 1); // ['dog': 2, 'cat': 1]
  60.    * Dictionary.remove('dog'); // [cat: 1]
  61.    */
  62.   remove (key) {
  63.     delete this.getContainer()[key];
  64.   }
  66.   /**
  67.    * Returns the underlying array.
  68.    * 
  69.    * @returns {Array} Returns the underlying array.
  70.    * @example Dictionary.add('dog', 2); // ['dog': 2]
  71.    * Dictionary.add('cat', 1); // ['dog': 2, 'cat': 1]
  72.    * Dictionary.display(); // ['dog': 2, 'cat': 1]
  73.    */
  74.   display () {
  75.     return this.getContainer();
  76.   }
  78.   /**
  79.    * Counts all key value pairs.
  80.    * 
  81.    * @returns {Number} Returns number of all key value pairs.
  82.    * @example Dictionary.display(); // ['dog': 2, 'cat': 1]
  83.    * Dictionary.count(); // 2
  84.    * Dictionary.display(); // ['dog': 2, 'cat': 1, 'pig': 4]
  85.    * Dictionary.count(); // 3
  86.    */
  87.   count () {
  88.     let number = 0;
  89.     for (const key in Object.keys(this.getContainer())) {
  90.       number++;
  91.     }
  92.     return number;
  93.   }
  95.   /**
  96.    * Deletes all key value pairs.
  97.    * 
  98.    * @example Dictionary.display(); // ['dog': 2, 'cat': 1]
  99.    * Dictionary.clear(); // []
  100.    * 
  101.    */
  102.   clear () {
  103.     this.setContainer([]);
  104.   }
  106. }
  107. module.exports = Dictionary;