Add Trie.

Author: trekhleb

src/data-structures/trie/Trie.js

@@ -26,7 +26,7 @@ export default class Trie {
     return lastCharacter.suggestChildren();
   }
 
-  doesWordExists(word) {
+  doesWordExist(word) {
     return !!this.getLastCharacterNode(word);
   }
 

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

@@ -44,8 +44,8 @@ describe('Trie', () => {
     trie.addWord('car');
     trie.addWord('caption');
 
-    expect(trie.doesWordExists('cat')).toBeTruthy();
-    expect(trie.doesWordExists('cap')).toBeTruthy();
-    expect(trie.doesWordExists('call')).toBeFalsy();
+    expect(trie.doesWordExist('cat')).toBeTruthy();
+    expect(trie.doesWordExist('cap')).toBeTruthy();
+    expect(trie.doesWordExist('call')).toBeFalsy();
   });
 });