react-predictive-text/Trie.js

A React component that finishes users' words.

class Trie {
	constructor() {
		this.storage = {};
	}

	add(word) {
		var currentStorage = this.storage;
		word.split("").forEach((letter) => {
			if (!currentStorage[letter]) {  // if letter does not exist at current level
			  currentStorage[letter] = {}  //add it.
 			}
 			currentStorage = currentStorage[letter]  // navigate to letter's storage.
		});
	}

	retrieve(fragment) {
		var possibleWords = [];

		var currentStorage = this.storage;

		fragment.split("").forEach((letter) => {
			if (!currentStorage) {  //if nothing in storage
				return null;  //break out of forEach loop.
			} else {  // else
				let uc = letter.toUpperCase();
				let lc = letter.toLowerCase();
			  currentStorage = currentStorage[lc] ||  currentStorage[uc] // navigate to letter's storage.
			}
		})  // now we are at common storage for the fragment.  So we just need to
		    //Generate possible words.
		function generateWords(currentWord, storage) {
			if(!storage) return; // if storage is undefined then there are no possibilities left.
			if (Object.keys(storage).length === 0) {//if storage is empty
			  //we are done with the word, so push it to possibleWords.
			  possibleWords.push(currentWord);
			} else {//otherwise,
			  //for each key in the storage
			  for (var key in storage) {
			    //add key to currentWord
			    currentWord += key;
			    //recurse using currentWord and the new storage.
			    generateWords(currentWord, storage[key])
			    //remove key from currentWord so it won't be added next pass.
			    currentWord = currentWord.split('').slice(0, currentWord.length-1).join('');
			  }
			}
		}
		generateWords(fragment, currentStorage);
		return possibleWords;
	}

	show() {
		console.log(this.storage);
	}
}

module.exports = Trie;