map-tree v1.1.1

map-tree

MapTree structure, allows Maps to lookup elements in its Map children in a BFS way.

• Solves Map inheritance
• Allows overrides by setting keys on parents
• Similar interface to the Map you love
• Uses Map and Set under the hood to keep lookups and changes fast
• Fundamental algorithm used is Breadth-first search (BSF)
• Does not test for cycles, thus does not support graphs
• Dependency free

Installation

npm install map-tree --save

Usage

const MapTree = require("map-tree");

const foodMap = new MapTree([["steak", {value: 1}]]);

const fruitMap = new MapTree();
fruitMap.set("banana", {value: 2});
fruitMap.set("apple", {value: 3});

foodMap.children.add(fruitMap);
foodMap.get("banana", true); // {value: 2}
foodMap.has("steak"); // true
foodMap.has("apple"); // false (not traversing)

for (let [key, value] of foodMap.entries(true)) {
    // will traverse children too!
}

Syntax

new MapTree([iterable [, children]]);

• iterable : Array or iterable object of key-value pairs.

• children : Array or iterable object of MapTree objects defining the children of the new object.

Properties

• Map.prototype.size : Returns the number of key/value pairs in the MapTree object. It does not include children.

• Map.prototype.children : Returns the MapTree children Set. The Set can be changed to add/remove/clear children. Property can be set provided an array or iterable object of MapTree objects to replace all children.

Methods

• Map.prototype.clear() : Removes all key/value pairs from the MapTree object. Does not clear the children.

• Map.prototype.delete(key) : Removes element from MapTree and returns true if the element did not exist, or false if the element did not. It will not delete from the children.

• Map.prototype.entries([traverse]) : Returns a new Iterator object that contains an array of key, value for each element in the MapTree object in insertion order. If traverse is true, the Iterator will include children key, value in a BFS order.

• Map.prototype.forEach(callbackFn [, traverse [, thisArg]]) : Calls callbackFn once for each key-value pair present in the MapTree object, in insertion order. If traverse is true, key-value pair present in children will be provided in BFS order. If a thisArg parameter is provided to forEach, it will be used as the this value for each callback.

• Map.prototype.get(key[, traverse]) : Returns the value associated to the key, or undefined if there is none. If traverse is true, the key will be matched with children in BFS order.

• Map.prototype.has(key[, traverse]) : Returns a boolean asserting whether a value has been associated to the key in the MapTree object or not. If traverse is true, the key will be matched with children in BFS order.

• Map.prototype.keys([traverse]) : Returns a new Iterator object that contains the keys for each element in the MapTree object in insertion order. If traverse is true, the Iterator will include children keys in a BFS order.

• Map.prototype.set(key, value) : Sets the value for the key in the MapTree object. Returns the MapTree object.

• Map.prototype.values([traverse]) : Returns a new Iterator object that contains the values for each element in the MapTree object in insertion order. If traverse is true, the Iterator will include children values in a BFS order.

• Map.prototype[\@\@iterator]() : Returns a new Iterator object that contains an array of key, value for each element in the MapTree object in insertion order. It does not include children.