Add Trie.deleteWord and TrieNode.removeChild (#181)

src/data-structures/trie/__test__/Trie.test.js

@@ -23,6 +23,18 @@ describe('Trie', () => {
     expect(trie.head.getChild('c').getChild('a').getChild('t').toString()).toBe('t*');
   });
 
+  it('should delete words from trie', () => {
+    const trie = new Trie();
+
+    trie.addWord('carpet');
+    trie.addWord('car');
+    expect(trie.doesWordExist('carpet')).toBe(true);
+
+    trie.deleteWord('carpet');
+    expect(trie.doesWordExist('carpet')).toEqual(false);
+    expect(trie.doesWordExist('car')).toEqual(true);
+  });
+
   it('should suggests next characters', () => {
     const trie = new Trie();
 

src/data-structures/trie/__test__/TrieNode.test.js

@@ -18,6 +18,36 @@ describe('TrieNode', () => {
     expect(trieNode.toString()).toBe('c:a,o');
   });
 
+  describe('removing child nodes', () => {
+    it('should delete child node if the child node has NO children', () => {
+      const trieNode = new TrieNode('c');
+      trieNode.addChild('a');
+      expect(trieNode.hasChild('a')).toBe(true);
+
+      trieNode.removeChild('a');
+      expect(trieNode.hasChild('a')).toBe(false);
+    });
+
+    it('should NOT delete child node if the child node has children', () => {
+      const trieNode = new TrieNode('c');
+      trieNode.addChild('a');
+      const childNode = trieNode.getChild('a');
+      childNode.addChild('r');
+
+      trieNode.removeChild('a');
+      expect(trieNode.hasChild('a')).toEqual(true);
+    });
+
+    it('should NOT delete child node if the child node completes a word', () => {
+      const trieNode = new TrieNode('c');
+      const IS_COMPLETE_WORD = true;
+      trieNode.addChild('a', IS_COMPLETE_WORD);
+
+      trieNode.removeChild('a');
+      expect(trieNode.hasChild('a')).toEqual(true);
+    });
+  });
+
   it('should get child nodes', () => {
     const trieNode = new TrieNode('c');