Fix examples

Author: tshemsedinov

JavaScript/b-yield.js

@@ -1,9 +1,10 @@
 'use strict';
 
-function* counter(begin, end, delta) {
+function* counter(begin, end, delta = 1) {
   let value = begin;
   while (end > value) {
     value += delta;
+    if (value > end) return;
     yield value;
   }
 }

JavaScript/c-return.js

@@ -4,7 +4,7 @@ function* ids(...args) {
   let i = 0;
   while (args.length > i) {
     const id = args[i++];
-    if (id === undefined) return -1;
+    if (id === undefined) return;
     yield id;
   }
 }

JavaScript/d-for-of.js

@@ -4,7 +4,7 @@ function* ids(...args) {
   let i = 0;
   while (args.length > i) {
     const id = args[i++];
-    if (id === undefined) return -1;
+    if (id === undefined) return;
     yield id;
   }
 }

JavaScript/e-spread.js

@@ -4,10 +4,10 @@ function* ids(...args) {
   let i = 0;
   while (args.length > i) {
     const id = args[i++];
-    if (id === undefined) return -1;
+    if (id === undefined) return;
     yield id;
   }
 }
 
 const id = ids(1011, 1078, 1292, 1731, undefined, 1501, 1550);
-console.log([...id]);
+console.log(...id);