Add iteratee arity hints to forEach methods. [closes #2277]

fp/_baseConvert.js

@@ -189,25 +189,22 @@ function baseConvert(util, name, func, options) {
         if (!isFunction(func)) {
           return mixin(func, Object(source));
         }
-        var methods = [],
+        var pairs = [];
-            methodNames = [];
-
         each(keys(source), function(key) {
           var value = source[key];
           if (isFunction(value)) {
-            methodNames.push(key);
+            pairs.push([key, func.prototype[key]]);
-            methods.push(func.prototype[key]);
           }
         });
 
         mixin(func, Object(source));
 
-        each(methodNames, function(methodName, index) {
+        each(pairs, function(pair) {
-          var method = methods[index];
+          var value = pair[1];
-          if (isFunction(method)) {
+          if (isFunction(value)) {
-            func.prototype[methodName] = method;
+            func.prototype[pair[0]] = value;
           } else {
-            delete func.prototype[methodName];
+            delete func.prototype[pair[0]];
           }
         });
         return func;

lodash.js

@@ -8500,9 +8500,8 @@
      * // => Logs 'a' then 'b' (iteration order is not guaranteed).
      */
     function forEach(collection, iteratee) {
-      return (typeof iteratee == 'function' && isArray(collection))
+      var func = isArray(collection) ? arrayEach : baseEach;
-        ? arrayEach(collection, iteratee)
+      return func(collection, getIteratee(iteratee, 3));
-        : baseEach(collection, getIteratee(iteratee));
     }
 
     /**
@@ -8526,9 +8525,8 @@
      * // => Logs `2` then `1`.
      */
     function forEachRight(collection, iteratee) {
-      return (typeof iteratee == 'function' && isArray(collection))
+      var func = isArray(collection) ? arrayEachRight : baseEachRight;
-        ? arrayEachRight(collection, iteratee)
+      return func(collection, getIteratee(iteratee, 3));
-        : baseEachRight(collection, getIteratee(iteratee));
     }
 
     /**
@@ -12103,7 +12101,7 @@
     function forIn(object, iteratee) {
       return object == null
         ? object
-        : baseFor(object, getIteratee(iteratee), keysIn);
+        : baseFor(object, getIteratee(iteratee, 3), keysIn);
     }
 
     /**
@@ -12135,7 +12133,7 @@
     function forInRight(object, iteratee) {
       return object == null
         ? object
-        : baseForRight(object, getIteratee(iteratee), keysIn);
+        : baseForRight(object, getIteratee(iteratee, 3), keysIn);
     }
 
     /**
@@ -12167,7 +12165,7 @@
      * // => Logs 'a' then 'b' (iteration order is not guaranteed).
      */
     function forOwn(object, iteratee) {
-      return object && baseForOwn(object, getIteratee(iteratee));
+      return object && baseForOwn(object, getIteratee(iteratee, 3));
     }
 
     /**
@@ -12197,7 +12195,7 @@
      * // => Logs 'b' then 'a' assuming `_.forOwn` logs 'a' then 'b'.
      */
     function forOwnRight(object, iteratee) {
-      return object && baseForOwnRight(object, getIteratee(iteratee));
+      return object && baseForOwnRight(object, getIteratee(iteratee, 3));
     }
 
     /**

test/test-fp.js

@@ -1178,6 +1178,35 @@
       });
     });
   });
+
+  /*--------------------------------------------------------------------------*/
+
+  QUnit.module('forEach methods');
+
+  _.each(['forEach', 'forEachRight', 'forIn', 'forInRight', 'forOwn', 'forOwnRight'], function(methodName) {
+    var func = fp[methodName];
+
+    QUnit.test('`fp.' + methodName + '` should provide `value` to `iteratee`', function(assert) {
+      assert.expect(2);
+
+      var args;
+
+      func(function() {
+        args || (args = slice.call(arguments));
+      })(['a']);
+
+      assert.deepEqual(args, ['a']);
+
+      args = undefined;
+
+      func(function() {
+        args || (args = slice.call(arguments));
+      })({ 'a': 1 });
+
+      assert.deepEqual(args, [1]);
+    });
+  });
+
   /*--------------------------------------------------------------------------*/
 
   QUnit.module('fp.getOr');