Add fromIndex param to _.findIndex and _.findLastIndex.

lodash.js

@@ -717,12 +717,13 @@
    * @private
    * @param {Array} array The array to search.
    * @param {Function} predicate The function invoked per iteration.
+   * @param {number} fromIndex The index to search from.
    * @param {boolean} [fromRight] Specify iterating from right to left.
    * @returns {number} Returns the index of the matched value, else `-1`.
    */
-  function baseFindIndex(array, predicate, fromRight) {
+  function baseFindIndex(array, predicate, fromIndex, fromRight) {
     var length = array.length,
-        index = fromRight ? length : -1;
+        index = fromIndex + (fromRight ? 1 : -1);
 
     while ((fromRight ? index-- : ++index < length)) {
       if (predicate(array[index], index, array)) {
@@ -1040,7 +1041,7 @@
    */
   function indexOfNaN(array, fromIndex, fromRight) {
     var length = array.length,
-        index = fromIndex + (fromRight ? 0 : -1);
+        index = fromIndex + (fromRight ? 1 : -1);
 
     while ((fromRight ? index-- : ++index < length)) {
       var other = array[index];
@@ -6428,6 +6429,7 @@
      * @param {Array} array The array to search.
      * @param {Array|Function|Object|string} [predicate=_.identity]
      *  The function invoked per iteration.
+     * @param {number} [fromIndex=0] The index to search from.
      * @returns {number} Returns the index of the found element, else `-1`.
      * @example
      *
@@ -6452,10 +6454,16 @@
      * _.findIndex(users, 'active');
      * // => 2
      */
-    function findIndex(array, predicate) {
+    function findIndex(array, predicate, fromIndex) {
-      return (array && array.length)
+      var length = array ? array.length : 0;
-        ? baseFindIndex(array, getIteratee(predicate, 3))
+      if (!length) {
-        : -1;
+        return -1;
+      }
+      var index = fromIndex == null ? 0 : toInteger(fromIndex);
+      if (index < 0) {
+        index = nativeMax(length + index, 0);
+      }
+      return baseFindIndex(array, getIteratee(predicate, 3), index);
     }
 
     /**
@@ -6469,6 +6477,7 @@
      * @param {Array} array The array to search.
      * @param {Array|Function|Object|string} [predicate=_.identity]
      *  The function invoked per iteration.
+     * @param {number} [fromIndex=array.length-1] The index to search from.
      * @returns {number} Returns the index of the found element, else `-1`.
      * @example
      *
@@ -6493,10 +6502,19 @@
      * _.findLastIndex(users, 'active');
      * // => 0
      */
-    function findLastIndex(array, predicate) {
+    function findLastIndex(array, predicate, fromIndex) {
-      return (array && array.length)
+      var length = array ? array.length : 0;
-        ? baseFindIndex(array, getIteratee(predicate, 3), true)
+      if (!length) {
-        : -1;
+        return -1;
+      }
+      var index = length - 1;
+      if (fromIndex !== undefined) {
+        index = toInteger(fromIndex);
+        index = fromIndex < 0
+          ? nativeMax(length + index, 0)
+          : nativeMin(index, length - 1);
+      }
+      return baseFindIndex(array, getIteratee(predicate, 3), index, true);
     }
 
     /**
@@ -6643,11 +6661,11 @@
       if (!length) {
         return -1;
       }
-      fromIndex = toInteger(fromIndex);
+      var index = fromIndex == null ? 0 : toInteger(fromIndex);
-      if (fromIndex < 0) {
+      if (index < 0) {
-        fromIndex = nativeMax(length + fromIndex, 0);
+        index = nativeMax(length + index, 0);
       }
-      return baseIndexOf(array, value, fromIndex);
+      return baseIndexOf(array, value, index);
     }
 
     /**
@@ -6838,7 +6856,7 @@
         ) + 1;
       }
       if (value !== value) {
-        return indexOfNaN(array, index, true);
+        return indexOfNaN(array, index - 1, true);
       }
       while (index--) {
         if (array[index] === value) {
@@ -8414,7 +8432,7 @@
     function find(collection, predicate) {
       predicate = getIteratee(predicate, 3);
       if (isArray(collection)) {
-        var index = baseFindIndex(collection, predicate);
+        var index = baseFindIndex(collection, predicate, 0);
         return index > -1 ? collection[index] : undefined;
       }
       return baseFind(collection, predicate, baseEach);
@@ -8442,7 +8460,7 @@
     function findLast(collection, predicate) {
       predicate = getIteratee(predicate, 3);
       if (isArray(collection)) {
-        var index = baseFindIndex(collection, predicate, true);
+        var index = baseFindIndex(collection, predicate, collection.length - 1, true);
         return index > -1 ? collection[index] : undefined;
       }
       return baseFind(collection, predicate, baseEachRight);

test/test.js

@@ -7768,24 +7768,26 @@
 
   /*--------------------------------------------------------------------------*/
 
-  QUnit.module('lodash.indexOf');
+  QUnit.module('lodash.findIndex and lodash.indexOf');
 
-  (function() {
+  lodashStable.each(['findIndex', 'indexOf'], function(methodName) {
-    var array = [1, 2, 3, 1, 2, 3];
+    var array = [1, 2, 3, 1, 2, 3],
+        func = _[methodName],
+        resolve = methodName == 'findIndex' ? lodashStable.curry(lodashStable.eq) : identity;
 
-    QUnit.test('should return the index of the first matched value', function(assert) {
+    QUnit.test('`_.' + methodName + '` should return the index of the first matched value', function(assert) {
       assert.expect(1);
 
-      assert.strictEqual(_.indexOf(array, 3), 2);
+      assert.strictEqual(func(array, resolve(3)), 2);
     });
 
-    QUnit.test('should work with a positive `fromIndex`', function(assert) {
+    QUnit.test('`_.' + methodName + '` should work with a positive `fromIndex`', function(assert) {
       assert.expect(1);
 
-      assert.strictEqual(_.indexOf(array, 1, 2), 3);
+      assert.strictEqual(func(array, resolve(1), 2), 3);
     });
 
-    QUnit.test('should work with `fromIndex` >= `array.length`', function(assert) {
+    QUnit.test('`_.' + methodName + '` should work with `fromIndex` >= `array.length`', function(assert) {
       assert.expect(1);
 
       var values = [6, 8, Math.pow(2, 32), Infinity],
@@ -7793,52 +7795,52 @@
 
       var actual = lodashStable.map(values, function(fromIndex) {
         return [
-          _.indexOf(array, undefined, fromIndex),
+          func(array, resolve(undefined), fromIndex),
-          _.indexOf(array, 1, fromIndex),
+          func(array, resolve(1), fromIndex),
-          _.indexOf(array, '', fromIndex)
+          func(array, resolve(''), fromIndex)
         ];
       });
 
       assert.deepEqual(actual, expected);
     });
 
-    QUnit.test('should work with a negative `fromIndex`', function(assert) {
+    QUnit.test('`_.' + methodName + '` should work with a negative `fromIndex`', function(assert) {
       assert.expect(1);
 
-      assert.strictEqual(_.indexOf(array, 2, -3), 4);
+      assert.strictEqual(func(array, resolve(2), -3), 4);
     });
 
-    QUnit.test('should work with a negative `fromIndex` <= `-array.length`', function(assert) {
+    QUnit.test('`_.' + methodName + '` should work with a negative `fromIndex` <= `-array.length`', function(assert) {
       assert.expect(1);
 
       var values = [-6, -8, -Infinity],
           expected = lodashStable.map(values, alwaysZero);
 
       var actual = lodashStable.map(values, function(fromIndex) {
-        return _.indexOf(array, 1, fromIndex);
+        return func(array, resolve(1), fromIndex);
       });
 
       assert.deepEqual(actual, expected);
     });
 
-    QUnit.test('should treat falsey `fromIndex` values as `0`', function(assert) {
+    QUnit.test('`_.' + methodName + '` should treat falsey `fromIndex` values as `0`', function(assert) {
       assert.expect(1);
 
       var expected = lodashStable.map(falsey, alwaysZero);
 
       var actual = lodashStable.map(falsey, function(fromIndex) {
-        return _.indexOf(array, 1, fromIndex);
+        return func(array, resolve(1), fromIndex);
       });
 
       assert.deepEqual(actual, expected);
     });
 
-    QUnit.test('should coerce `fromIndex` to an integer', function(assert) {
+    QUnit.test('`_.' + methodName + '` should coerce `fromIndex` to an integer', function(assert) {
       assert.expect(1);
 
-      assert.strictEqual(_.indexOf(array, 2, 1.2), 1);
+      assert.strictEqual(func(array, resolve(2), 1.2), 1);
     });
-  }());
+  });
 
   /*--------------------------------------------------------------------------*/
 
@@ -13114,24 +13116,26 @@
 
   /*--------------------------------------------------------------------------*/
 
-  QUnit.module('lodash.lastIndexOf');
+  QUnit.module('lodash.findLastIndex and lodash.lastIndexOf');
 
-  (function() {
+  lodashStable.each(['findLastIndex', 'lastIndexOf'], function(methodName) {
-    var array = [1, 2, 3, 1, 2, 3];
+    var array = [1, 2, 3, 1, 2, 3],
+        func = _[methodName],
+        resolve = methodName == 'findLastIndex' ? lodashStable.curry(lodashStable.eq) : identity;
 
-    QUnit.test('should return the index of the last matched value', function(assert) {
+    QUnit.test('`_.' + methodName + '` should return the index of the last matched value', function(assert) {
       assert.expect(1);
 
-      assert.strictEqual(_.lastIndexOf(array, 3), 5);
+      assert.strictEqual(func(array, resolve(3)), 5);
     });
 
-    QUnit.test('should work with a positive `fromIndex`', function(assert) {
+    QUnit.test('`_.' + methodName + '` should work with a positive `fromIndex`', function(assert) {
       assert.expect(1);
 
-      assert.strictEqual(_.lastIndexOf(array, 1, 2), 0);
+      assert.strictEqual(func(array, resolve(1), 2), 0);
     });
 
-    QUnit.test('should work with `fromIndex` >= `array.length`', function(assert) {
+    QUnit.test('`_.' + methodName + '` should work with `fromIndex` >= `array.length`', function(assert) {
       assert.expect(1);
 
       var values = [6, 8, Math.pow(2, 32), Infinity],
@@ -13139,35 +13143,35 @@
 
       var actual = lodashStable.map(values, function(fromIndex) {
         return [
-          _.lastIndexOf(array, undefined, fromIndex),
+          func(array, resolve(undefined), fromIndex),
-          _.lastIndexOf(array, 1, fromIndex),
+          func(array, resolve(1), fromIndex),
-          _.lastIndexOf(array, '', fromIndex)
+          func(array, resolve(''), fromIndex)
         ];
       });
 
       assert.deepEqual(actual, expected);
     });
 
-    QUnit.test('should work with a negative `fromIndex`', function(assert) {
+    QUnit.test('`_.' + methodName + '` should work with a negative `fromIndex`', function(assert) {
       assert.expect(1);
 
-      assert.strictEqual(_.lastIndexOf(array, 2, -3), 1);
+      assert.strictEqual(func(array, resolve(2), -3), 1);
     });
 
-    QUnit.test('should work with a negative `fromIndex` <= `-array.length`', function(assert) {
+    QUnit.test('`_.' + methodName + '` should work with a negative `fromIndex` <= `-array.length`', function(assert) {
       assert.expect(1);
 
       var values = [-6, -8, -Infinity],
           expected = lodashStable.map(values, alwaysZero);
 
       var actual = lodashStable.map(values, function(fromIndex) {
-        return _.lastIndexOf(array, 1, fromIndex);
+        return func(array, resolve(1), fromIndex);
       });
 
       assert.deepEqual(actual, expected);
     });
 
-    QUnit.test('should treat falsey `fromIndex` values correctly', function(assert) {
+    QUnit.test('`_.' + methodName + '` should treat falsey `fromIndex` values correctly', function(assert) {
       assert.expect(1);
 
       var expected = lodashStable.map(falsey, function(value) {
@@ -13175,18 +13179,18 @@
       });
 
       var actual = lodashStable.map(falsey, function(fromIndex) {
-        return _.lastIndexOf(array, 3, fromIndex);
+        return func(array, resolve(3), fromIndex);
       });
 
       assert.deepEqual(actual, expected);
     });
 
-    QUnit.test('should coerce `fromIndex` to an integer', function(assert) {
+    QUnit.test('`_.' + methodName + '` should coerce `fromIndex` to an integer', function(assert) {
       assert.expect(1);
 
-      assert.strictEqual(_.lastIndexOf(array, 2, 4.2), 4);
+      assert.strictEqual(func(array, resolve(2), 4.2), 4);
     });
-  }());
+  });
 
   /*--------------------------------------------------------------------------*/