maps-javascript

data_structures/maps/maps.js

@@ -0,0 +1,70 @@
+
+
+// A map is a data structure that stores data in key/values pair where 
+// every key is unique.
+
+/* Maps */
+
+let myMap = function() {
+	this.collection = {};
+	this.count = 0;
+	this.size = function() {
+		return this.count;
+	};
+	this.set = function(key, value) {
+		this.collection[key] = value;
+		this.count++;
+	};
+	this.has = function(key) {
+		return (key in this.collection);
+	};
+	this.get = function(key) {
+		return (key in this.collection) ? this.collection[key] : null;
+	};
+	this.delete = function(key) {
+		if (key in this.collection) {
+			delete this.collection[key];
+			this.count--;
+		}
+	};
+	this.values = function() {
+		let result = new Array();
+		for (let key of Object.keys(this.collection)) {
+			result.push(this.collection[key]);
+		};
+		return (result.length > 0) ? result : null;
+	};
+	this.clear = function() {
+		this.collection = {};
+		this.count = 0;
+	};
+};
+
+let map = new myMap();
+map.set('arms', 2);
+map.set('fingers', 10);
+map.set('eyes', 2);
+map.set('belley button', 1);
+
+console.log(map.get('fingers'));
+console.log(map.size());
+console.log(map.values());
+
+let map2 = new Map();
+map2.has('hands');
+map2.entries();
+
+let keyObj = {},
+    keyFunc = function() {};
+
+map2.set('hello', 'string value');
+map2.set(keyObj, 'obj value');
+map2.set(keyFunc, 'func value');
+map2.set(NaN, 'NaN value')
+
+console.log(map2.size);
+
+console.log(map2.get('hello'));
+console.log(map2.get(keyObj));
+console.log(map2.get(keyFunc));
+console.log(map2.get(NaN));