From 0361fe5cf8e2dbb08461f4973152bb0c2e809fa7 Mon Sep 17 00:00:00 2001
From: Nicolas DUBIEN <dubzzz@users.noreply.github.com>
Date: Tue, 24 Jul 2018 11:26:22 +0200
Subject: [PATCH] Fix knuthMorrisPratt for empty word request (#101)

---
 .../knuth-morris-pratt/__test__/knuthMorrisPratt.test.js      | 4 ++--
 src/algorithms/string/knuth-morris-pratt/knuthMorrisPratt.js  | 4 ++++
 2 files changed, 6 insertions(+), 2 deletions(-)

diff --git a/src/algorithms/string/knuth-morris-pratt/__test__/knuthMorrisPratt.test.js b/src/algorithms/string/knuth-morris-pratt/__test__/knuthMorrisPratt.test.js
index 42e6f81c..17f6a696 100644
--- a/src/algorithms/string/knuth-morris-pratt/__test__/knuthMorrisPratt.test.js
+++ b/src/algorithms/string/knuth-morris-pratt/__test__/knuthMorrisPratt.test.js
@@ -2,8 +2,8 @@ import knuthMorrisPratt from '../knuthMorrisPratt';
 
 describe('knuthMorrisPratt', () => {
   it('should find word position in given text', () => {
-    expect(knuthMorrisPratt('', '')).toBe(-1);
-    expect(knuthMorrisPratt('a', '')).toBe(-1);
+    expect(knuthMorrisPratt('', '')).toBe(0);
+    expect(knuthMorrisPratt('a', '')).toBe(0);
     expect(knuthMorrisPratt('a', 'a')).toBe(0);
     expect(knuthMorrisPratt('abcbcglx', 'abca')).toBe(-1);
     expect(knuthMorrisPratt('abcbcglx', 'bcgl')).toBe(3);
diff --git a/src/algorithms/string/knuth-morris-pratt/knuthMorrisPratt.js b/src/algorithms/string/knuth-morris-pratt/knuthMorrisPratt.js
index 4c008e44..e4344b77 100644
--- a/src/algorithms/string/knuth-morris-pratt/knuthMorrisPratt.js
+++ b/src/algorithms/string/knuth-morris-pratt/knuthMorrisPratt.js
@@ -30,6 +30,10 @@ function buildPatternTable(word) {
  * @return {number}
  */
 export default function knuthMorrisPratt(text, word) {
+  if (word.length === 0) {
+    return 0;
+  }
+
   let textIndex = 0;
   let wordIndex = 0;