up

1-js/03-code-quality/02-coding-style/article.md

@@ -212,7 +212,7 @@ If you are writing several "helper" functions and the code to use them, then the
     }
 
     // *!*the code which uses them*/!*
-    var elem = createElement();
+    let elem = createElement();
     setHandler(elem);
     walkAround();
     ```
@@ -220,7 +220,7 @@ If you are writing several "helper" functions and the code to use them, then the
 
     ```js
     // *!*the code which uses the functions*/!*
-    var elem = createElement();
+    let elem = createElement();
     setHandler(elem);
     walkAround();
 

1-js/04-object-basics/01-object/8-multiply-numeric/_js.view/test.js

@@ -1,6 +1,6 @@
 describe("multiplyNumeric", function() {
   it("multiplies all numeric properties by 2", function() {
-    var menu = {
+    let menu = {
       width: 200,
       height: 300,
       title: "My menu"
@@ -14,5 +14,5 @@ describe("multiplyNumeric", function() {
   it("returns nothing", function() {
     assert.isUndefined( multiplyNumeric({}) );
   });
-  
-});
+
+});

1-js/04-object-basics/06-constructor-new/1-two-functions-one-object/task.md

@@ -10,8 +10,8 @@ Is it possible to create functions `A` and `B` such as `new A()==new B()`?
 function A() { ... }
 function B() { ... }
 
-var a = new A;
-var b = new B;
+let a = new A;
+let b = new B;
 
 alert( a == b ); // true
 ```

1-js/04-object-basics/06-constructor-new/article.md

@@ -1,4 +1,4 @@
-# Using "new" to create objects
+# Constructor, operator "new" 
 
 The regular `{...}` syntax allows to create one object. But often we need to create many similar objects.
 
@@ -62,7 +62,7 @@ let user = {
 };
 ```
 
-Now if we want to create other users, we can call `new User("Ann")`, `new User("Alice")` and so on. Much shorter than using literals every time, and also reads well. 
+Now if we want to create other users, we can call `new User("Ann")`, `new User("Alice")` and so on. Much shorter than using literals every time, and also reads well.
 
 That's the main purpose of constructors -- to implement reusable object creation code.
 
@@ -85,7 +85,7 @@ let user = new function() {
 The constructor can't be called again, because it is not saved anywhere, just created and called. So this trick aims to encapsulate the code for a single complex object only.
 ````
 
-## Dual-use constructors: new.target 
+## Dual-use constructors: new.target
 
 Inside a function, we can check how it is called with `new` or without it, using a special `new.target` property.
 
@@ -131,7 +131,7 @@ In other words, `return` with an object returns that object, otherwise `this` is
 
 For instance, here `return` overrides `this` by returning an object:
 
-```js run 
+```js run
 function BigUser() {
 
   this.name = "John";
@@ -144,7 +144,7 @@ alert( new BigUser().name );  // Godzilla, got that object
 
 And here's an example with an empty `return` (or we could place a primitive after it, doesn't matter):
 
-```js run 
+```js run
 function SmallUser() {
 
   this.name = "John";
@@ -195,7 +195,7 @@ let john = new User("John");
 john.sayHi(); // My name is: John
 */!*
 
-/* 
+/*
 john = {
    name: "John",
    sayHi: function() { ... }
@@ -208,9 +208,6 @@ john = {
 - Constructor functions or, shortly, constructors, are regular functions, but there's a common agreement to name them with capital letter first.
 - Constructor functions should only be called using `new`. Such call implies a creation of empty `this` at the start and returning the populated one at the end.
 
-We can use constructor functions to make multiple similar objects. But the topic is much deeper than described here. So we'll return it later and cover more in-depth. 
+We can use constructor functions to make multiple similar objects. But the topic is much deeper than described here. So we'll return it later and cover more in-depth.
 
 As of now, it's important to understand what `new` is, because JavaScript provides constructor functions for many built-in language objects: like `Date` for dates, `Set` for sets and others that we plan to study.
-
-
-

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

@@ -22,7 +22,7 @@ How to delete an element from the array?
 The arrays are objects, so we can try to use `delete`:
 
 ```js run
-var arr = ["I", "go", "home"];
+let arr = ["I", "go", "home"];
 
 delete arr[1]; // remove "go"
 

1-js/05-data-types/07-map-set-weakmap-weakset/02-filter-anagrams/solution.md

@@ -20,7 +20,7 @@ function aclean(arr) {
 *!*
     let sorted = word.toLowerCase().split('').sort().join(''); // (*)
 */!*
-    map.set(sorted, word); 
+    map.set(sorted, word);
   }
 
   return Array.from(map.values());
@@ -36,7 +36,7 @@ Letter-sorting is done by the chain of calls in the line `(*)`.
 For convenience let's split it into multiple lines:
 
 ```js
-var sorted = arr[i] // PAN
+let sorted = arr[i] // PAN
   .toLowerCase() // pan
   .split('') // ['p','a','n']
   .sort() // ['a','n','p']
@@ -61,10 +61,10 @@ That's how the solution can look:
 
 ```js run
 function aclean(arr) {
-  var obj = {};
+  let obj = {};
 
-  for (var i = 0; i < arr.length; i++) {
-    var sorted = arr[i].toLowerCase().split("").sort().join("");
+  for (let i = 0; i < arr.length; i++) {
+    let sorted = arr[i].toLowerCase().split("").sort().join("");
     obj[sorted] = arr[i];
   }
 
@@ -75,7 +75,3 @@ let arr = ["nap", "teachers", "cheaters", "PAN", "ear", "era", "hectares"];
 
 alert( aclean(arr) );
 ```
-
-
-
-

1-js/05-data-types/10-date/2-get-week-day/_js.view/solution.js

@@ -1,5 +1,5 @@
 function getWeekDay(date) {
-  var days = ['SU', 'MO', 'TU', 'WE', 'TH', 'FR', 'SA'];
+  let days = ['SU', 'MO', 'TU', 'WE', 'TH', 'FR', 'SA'];
 
   return days[date.getDay()];
 }

1-js/05-data-types/10-date/3-weekday/_js.view/solution.js

@@ -1,6 +1,6 @@
 function getLocalDay(date) {
 
-  var day = date.getDay();
+  let day = date.getDay();
 
   if (day == 0) { // weekday 0 (sunday) is 7 in european
     day = 7;

1-js/05-data-types/10-date/3-weekday/solution.md

@@ -1,7 +1,7 @@
 ```js run
 function getLocalDay(date) {
 
-  var day = date.getDay();
+  let day = date.getDay();
 
   if (day == 0) { // 0 becomes 7
     day = 7;

1-js/05-data-types/10-date/4-get-date-ago/_js.view/test.js

@@ -18,8 +18,8 @@ describe("getDateAgo", function() {
   });
 
   it("does not modify the given date", function() {
-    var date = new Date(2015, 0, 2);
-    var dateCopy = new Date(date);
+    let date = new Date(2015, 0, 2);
+    let dateCopy = new Date(date);
     getDateAgo(dateCopy, 100);
     assert.equal(date.getTime(), dateCopy.getTime());
   });

1-js/05-data-types/10-date/8-format-date-relative/_js.view/solution.js

@@ -12,7 +12,7 @@ function formatDate(date) {
     return sec + ' sec. ago';
   }
 
-  var min = Math.floor(diff / 60000); // convert diff to minutes
+  let min = Math.floor(diff / 60000); // convert diff to minutes
   if (min < 60) {
     return min + ' min. ago';
   }

1-js/05-data-types/10-date/8-format-date-relative/solution.md

@@ -14,7 +14,7 @@ function formatDate(date) {
     return sec + ' sec. ago';
   }
 
-  var min = Math.floor(diff / 60000); // convert diff to minutes
+  let min = Math.floor(diff / 60000); // convert diff to minutes
   if (min < 60) {
     return min + ' min. ago';
   }

1-js/06-advanced-functions/03-closure/article.md

@@ -524,7 +524,7 @@ Lexical Environment objects that we've been talking about are subjects to same m
 
     ```js
     function f() {
-      var value = Math.random();
+      let value = Math.random();
 
       return function() {};
     }
@@ -538,7 +538,7 @@ Lexical Environment objects that we've been talking about are subjects to same m
 
     ```js
     function f() {
-      var value = 123;
+      let value = 123;
 
       function g() {}
 
@@ -565,7 +565,7 @@ When it pauses, in console type `alert(value)`.
 
 ```js run
 function f() {
-  var value = Math.random();
+  let value = Math.random();
 
   function g() {
     debugger; // in console: type alert( value ); No such variable!
@@ -574,7 +574,7 @@ function f() {
   return g;
 }
 
-var g = f();
+let g = f();
 g();
 ```
 
@@ -623,7 +623,7 @@ From the first sight, `var` behaves similar to `let`. That is, declares a variab
 
 ```js run
 function sayHi() {
-  var phrase = "Hello"; // local variable, "var" instead of "let"
+  let phrase = "Hello"; // local variable, "var" instead of "let"
 
   alert(phrase); // Hello
 }
@@ -640,7 +640,7 @@ alert(phrase); // Error, phrase is not defined
 
     ```js
     if (true) {
-      var test = true; // use "var" instead of "let"
+      let test = true; // use "var" instead of "let"
     }
 
     *!*
@@ -653,7 +653,7 @@ alert(phrase); // Error, phrase is not defined
     The same thing for loops: `var` can not be block or loop-local:
 
     ```js
-    for(var i = 0; i < 10; i++) {
+    for(let i = 0; i < 10; i++) {
       // ...
     }
 
@@ -667,7 +667,7 @@ alert(phrase); // Error, phrase is not defined
     ```js
     function sayHi() {
       if (true) {
-        var phrase = "Hello";
+        let phrase = "Hello";
       }
 
       alert(phrase); // works
@@ -691,7 +691,7 @@ alert(phrase); // Error, phrase is not defined
       alert(phrase);
 
     *!*
-      var phrase;
+      let phrase;
     */!*
     }
     ```
@@ -701,7 +701,7 @@ alert(phrase); // Error, phrase is not defined
     ```js
     function sayHi() {
     *!*
-      var phrase;
+      let phrase;
     */!*
       phrase = "Hello";
 
@@ -717,7 +717,7 @@ alert(phrase); // Error, phrase is not defined
 
       *!*
       if (false) {
-        var phrase;
+        let phrase;
       }
       */!*
 
@@ -738,21 +738,21 @@ alert(phrase); // Error, phrase is not defined
       alert(phrase);  
 
     *!*
-      var phrase = "Hello";
+      let phrase = "Hello";
     */!*
     }
 
     sayHi();
     ```
 
-    The line `var phrase = "Hello"` has two actions in it: variable declaration `var` and assignment `=`.
+    The line `let phrase = "Hello"` has two actions in it: variable declaration `var` and assignment `=`.
 
     The declaration is processed at the start of function execution (hoisted), but the assignment is not. So the code works essentially like this:
 
     ```js run
     function sayHi() {
     *!*
-      var phrase; // variable is declared from the top...
+      let phrase; // variable is declared from the top...
     */!*
 
       alert(phrase); // undefined