Trie Node

TrieNode.js

class TrieNode {
	constructor (value, note="") {
		this.value = value;
		this.note = note;
		this.children = new Array(26);
	}

	addChildNode (char, value=null) {
		let index = char.charCodeAt(0) - 97;
		this.children[index] = this.children[index] || new TrieNode(null, char);

		if (value) {
			this.children[index].value = value;
		}
		return this.children[index];
	}

	print (level=0) {
		let indent = "";
		for (let i = 0; i < level * 2; i++) {
			indent += " ";
		}
		console.log(`${indent}${this.value} (${this.note})`);
		this.children.forEach(child => {
			if (child) {
				child.print(level+1);
			}
		})
	}

	insertKey (string, value) {
		const length = string.length;
		let currentNode = this;

		if (length == 0) {
			return;
		}

		for (let i = 0; i < length - 1; i++) {
			currentNode = currentNode.addChildNode(string.charAt(i));
		}

		currentNode.addChildNode(string.charAt(length-1), value);
	}

	hasKey (string) {

		let index = 0, currentNode = this, charCode;
		
		while(index < string.length) {

			charCode = string.charCodeAt(index++) - 97;
			if (currentNode.children[charCode]) {
				currentNode = currentNode.children[charCode];
			} else {
				return false;
			}
		}

		return !!currentNode.value;
	}

	getKey (string) {
		
		let index = 0, currentNode = this, char, charCode;

		while(index < string.length) {

			charCode = string.charCodeAt(index++) - 97;
			if (currentNode.children[charCode]) {
				currentNode = currentNode.children[charCode];
			} else {
				return "Not Found";
			}
		}

		return  currentNode.value || "Not Found";

	}
}

let root = new TrieNode(null, "root");

root.insertKey('xyz', 15);
root.insertKey('xyw', 25);
root.insertKey('xyz', 36);
root.insertKey('xyw', 42);
root.insertKey('xyzp', 15);

root.print();

console.log(root.hasKey('xyz'));
console.log(root.hasKey('xy'));
console.log(root.hasKey(''));

console.log(root.getKey('xyz'));
console.log(root.getKey('xy'));

// null (root)
//   null (x)
//     null (y)
//       42 (w)
//       36 (z)
//         15 (p)
// true
// false
// false
// 36
// Not Found
// [Finished in 0.1s]