fixes

1-js/04-object-basics/01-object/article.md

@@ -236,7 +236,7 @@ In that case the visitor may choose `__proto__` as the key, and the assignment l
 
 There is a way to make objects treat `__proto__` as a regular property, which we'll cover later, but first we need to know more about objects.
 
-There's also another data structure [Map](info:map-set-weakmap-weakset), that we'll learn in the chapter <info:map-set-weakmap-weakset>, which supports arbitrary keys.
+There's also another data structure [Map](info:map-set), that we'll learn in the chapter <info:map-set>, which supports arbitrary keys.
 ````
 
 

1-js/05-data-types/05-array-methods/11-array-unique/solution.md

@@ -36,4 +36,4 @@ So if `arr.length` is `10000` we'll have something like `10000*10000` = 100 mill
 
 So the solution is only good for small arrays.
 
-Further in the chapter <info:map-set-weakmap-weakset> we'll see how to optimize it.
+Further in the chapter <info:map-set> we'll see how to optimize it.

1-js/05-data-types/05-array-methods/9-shuffle/solution.md

@@ -45,7 +45,7 @@ for (let key in count) {
 }
 ```
 
-An example result (for V8, July 2017):
+An example result (depends on JS engine):
 
 ```js
 123: 250706

1-js/05-data-types/05-array-methods/article.md

@@ -581,8 +581,7 @@ Or in the form of a table, where each row represents a function call on the next
 |the fourth call|`6`|`4`|`10`|
 |the fifth call|`10`|`5`|`15`|
 
-
+Here we can clearly see how the result of the previous call becomes the first argument of the next one.
-As we can see, the result of the previous call becomes the first argument of the next one.
 
 We also can omit the initial value:
 
@@ -654,7 +653,7 @@ arr.map(func, thisArg);
 
 The value of `thisArg` parameter becomes `this` for `func`.
 
-For instance, here we use an object method as a filter and `thisArg` comes in handy:
+For instance, here we use an object method as a filter and `thisArg` helps with that:
 
 ```js run
 let user = {
@@ -726,7 +725,7 @@ These methods are the most used ones, they cover 99% of use cases. But there are
 
 For the full list, see the [manual](mdn:js/Array).
 
-From the first sight it may seem that there are so many methods, quite difficult to remember. But actually that's much easier than it seems.
+From the first sight it may seem that there are so many methods, quite difficult to remember. But actually that's much easier.
 
 Look through the cheat sheet just to be aware of them. Then solve the tasks of this chapter to practice, so that you have experience with array methods.