From 6402af7db9b952b24f3099c2b59832dd19541cfd Mon Sep 17 00:00:00 2001
From: John-David Dalton <john.david.dalton@gmail.com>
Date: Sun, 24 Jul 2016 08:29:39 -0700
Subject: [PATCH] Use `String#slice` instead of `String#indexOf` for
 `_.endsWith` and `_.startsWith`.

---
 lodash.js    |  6 ++++--
 test/test.js | 27 +++++++++++----------------
 2 files changed, 15 insertions(+), 18 deletions(-)

diff --git a/lodash.js b/lodash.js
index 6ec57f239..f717c2bdc 100644
--- a/lodash.js
+++ b/lodash.js
@@ -13703,8 +13703,9 @@
         ? length
         : baseClamp(toInteger(position), 0, length);
 
+      var end = position;
       position -= target.length;
-      return position >= 0 && string.indexOf(target, position) == position;
+      return position >= 0 && string.slice(position, end) == target;
     }
 
     /**
@@ -14152,7 +14153,8 @@
     function startsWith(string, target, position) {
       string = toString(string);
       position = baseClamp(toInteger(position), 0, string.length);
-      return string.lastIndexOf(baseToString(target), position) == position;
+      target = baseToString(target);
+      return string.slice(position, position + target.length) == target;
     }
 
     /**
diff --git a/test/test.js b/test/test.js
index 585d5f047..bc5b4ad55 100644
--- a/test/test.js
+++ b/test/test.js
@@ -5393,14 +5393,6 @@
 
       assert.strictEqual(_.endsWith(string, 'ab', 2.2), true);
     });
-
-    QUnit.test('should return `true` when `target` is an empty string regardless of `position`', function(assert) {
-      assert.expect(1);
-
-      assert.ok(lodashStable.every([-Infinity, NaN, -3, -1, 0, 1, 2, 3, 5, MAX_SAFE_INTEGER, Infinity], function(position) {
-        return _.endsWith(string, '', position, true);
-      }));
-    });
   }());
 
   /*--------------------------------------------------------------------------*/
@@ -20885,14 +20877,6 @@
 
       assert.strictEqual(_.startsWith(string, 'bc', 1.2), true);
     });
-
-    QUnit.test('should return `true` when `target` is an empty string regardless of `position`', function(assert) {
-      assert.expect(1);
-
-      assert.ok(lodashStable.every([-Infinity, NaN, -3, -1, 0, 1, 2, 3, 5, MAX_SAFE_INTEGER, Infinity], function(position) {
-        return _.startsWith(string, '', position, true);
-      }));
-    });
   }());
 
   /*--------------------------------------------------------------------------*/
@@ -20924,9 +20908,20 @@
       assert.expect(2);
 
       var position = isStartsWith ? 1 : 2;
+
       assert.strictEqual(func(string, 'b', Object(position)), true);
       assert.strictEqual(func(string, 'b', { 'toString': lodashStable.constant(String(position)) }), true);
     });
+
+    QUnit.test('should return `true` when `target` is an empty string regardless of `position`', function(assert) {
+      assert.expect(1);
+
+      var positions = [-Infinity, NaN, -3, -1, 0, 1, 2, 3, 5, MAX_SAFE_INTEGER, Infinity];
+
+      assert.ok(lodashStable.every(positions, function(position) {
+        return func(string, '', position);
+      }));
+    });
   });
 
   /*--------------------------------------------------------------------------*/