Just another update

Task/Averages-Arithmetic-mean/JavaScript/averages-arithmetic-mean-1.js

@@ -9,3 +9,4 @@ function mean(array)
 }
 
 alert( mean( [1,2,3,4,5] ) );   // 3
+alert( mean( [] ) );            // 0

Task/Averages-Arithmetic-mean/JavaScript/averages-arithmetic-mean-2.js

@@ -1,4 +1,9 @@
-function mean(a)
-{
- return a.length ? Functional.reduce('+', 0, a) / a.length : 0;
-}
+function mean(array) {
+    var sum = 0;
+    array.forEach(function(value){
+        sum += value;
+        });
+    return array.length ? sum / array.length : 0;
+    }
+
+alert( mean( [1,2,3,4,5] ) );   // 3

Task/Averages-Arithmetic-mean/JavaScript/averages-arithmetic-mean-3.js

@@ -0,0 +1,9 @@
+function mean(array) {
+    return !array.length ? 0
+        : array.reduce(function(pre, cur, i) {
+            return (pre * i + cur) / (i + 1);
+            });
+    }
+
+alert( mean( [1,2,3,4,5] ) );   // 3
+alert( mean( [] ) );            // 0

Task/Averages-Arithmetic-mean/JavaScript/averages-arithmetic-mean-4.js

@@ -0,0 +1,9 @@
+Array.prototype.mean = function() {
+    return !this.length ? 0
+        : this.reduce(function(pre, cur, i) {
+            return (pre * i + cur) / (i + 1);
+            });
+    }
+
+alert( [1,2,3,4,5].mean() );   // 3
+alert( [].mean() );            // 0

Task/Averages-Arithmetic-mean/JavaScript/averages-arithmetic-mean-5.js

@@ -0,0 +1,4 @@
+function mean(a)
+{
+ return a.length ? Functional.reduce('+', 0, a) / a.length : 0;
+}