Sync with upstream @ 69893128

.gitignore

@@ -21,3 +21,4 @@ sftp-config.json
 Thumbs.db
 
 
+/svgs

1-js/01-getting-started/1-intro/article.md

@@ -42,12 +42,20 @@ Spletni brskalniki uporabljajo različna imena za JavaScript engine:
 - [WebKit](<https://en.wikipedia.org/wiki/Safari_(web_browser)>) -- Safari
 - ...Obstajajo še druga imena kot je "ChakraCore" za Microsoft Edge ipd.
 
+<<<<<<< HEAD
 Zgornja poimenovanja si velja zapomniti saj se velikokrat pojavijo v raznih
 člankih razvijalcev, kjer jih navadno omenjajo kadar govorijo o podpori določene
 funkcionalnosti. Na primer: "lastnost X je podprta na V8", kar pomeni, da to
 lastnost lahko uporabimo na brskalnikih Chrome in Opera.
 
 ```smart header="Kako delujejo programski stroji (angl. *engines*)?"
+=======
+- [V8](https://en.wikipedia.org/wiki/V8_(JavaScript_engine)) -- in Chrome, Opera and Edge.
+- [SpiderMonkey](https://en.wikipedia.org/wiki/SpiderMonkey) -- in Firefox.
+- ...There are other codenames like "Chakra" for IE, "JavaScriptCore", "Nitro" and "SquirrelFish" for Safari, etc.
+
+The terms above are good to remember because they are used in developer articles on the internet. We'll use them too. For instance, if "a feature X is supported by V8", then it probably works in Chrome, Opera and Edge.
+>>>>>>> 6989312841d843f2350803ab552d9082437be569
 
 Programski stroji so precej zahtevni za razumevanje. A osnove so enostavne.
 
@@ -58,6 +66,7 @@ Programski stroji so precej zahtevni za razumevanje. A osnove so enostavne.
 Programski stroji opravijo dodatne optimizacije ob vsakem koraku v danem procesu. Pravtako imajo možnost opazovanja in analiziranje prevedene skripte, ki se poganja, in s tem dodatno optimizira strojno kodo glede na najdbe.
 ```
 
+<<<<<<< HEAD
 ## Kaj lahko stori JavaScript, ki se izvede v spletnem brskalniku?
 
 Sodobni JavaScript je "varen" programski jezik. To pomeni, da ne ponuja možnosti
@@ -116,6 +125,41 @@ Izjeme:
   da JavaScript ne more na skrivno prisluškovat ali omogočit spletno kamero ter
   podatke pošiljati
   [NSA](https://en.wikipedia.org/wiki/National_Security_Agency).
+=======
+## What can in-browser JavaScript do?
+
+Modern JavaScript is a "safe" programming language. It does not provide low-level access to memory or CPU, because it was initially created for browsers which do not require it.
+
+JavaScript's capabilities greatly depend on the environment it's running in. For instance, [Node.js](https://wikipedia.org/wiki/Node.js) supports functions that allow JavaScript to read/write arbitrary files, perform network requests, etc.
+
+In-browser JavaScript can do everything related to webpage manipulation, interaction with the user, and the webserver.
+
+For instance, in-browser JavaScript is able to:
+
+- Add new HTML to the page, change the existing content, modify styles.
+- React to user actions, run on mouse clicks, pointer movements, key presses.
+- Send requests over the network to remote servers, download and upload files (so-called [AJAX](https://en.wikipedia.org/wiki/Ajax_(programming)) and [COMET](https://en.wikipedia.org/wiki/Comet_(programming)) technologies).
+- Get and set cookies, ask questions to the visitor, show messages.
+- Remember the data on the client-side ("local storage").
+
+## What CAN'T in-browser JavaScript do?
+
+JavaScript's abilities in the browser are limited for the sake of a user's safety. The aim is to prevent an evil webpage from accessing private information or harming the user's data.
+
+Examples of such restrictions include:
+
+- JavaScript on a webpage may not read/write arbitrary files on the hard disk, copy them or execute programs. It has no direct access to OS functions.
+
+    Modern browsers allow it to work with files, but the access is limited and only provided if the user does certain actions, like "dropping" a file into a browser window or selecting it via an `<input>` tag.
+
+    There are ways to interact with camera/microphone and other devices, but they require a user's explicit permission. So a JavaScript-enabled page may not sneakily enable a web-camera, observe the surroundings and send the information to the [NSA](https://en.wikipedia.org/wiki/National_Security_Agency).
+- Different tabs/windows generally do not know about each other. Sometimes they do, for example when one window uses JavaScript to open the other one. But even in this case, JavaScript from one page may not access the other if they come from different sites (from a different domain, protocol or port).
+
+    This is called the "Same Origin Policy". To work around that, *both pages* must agree for data exchange and contain a special JavaScript code that handles it. We'll cover that in the tutorial.
+
+    This limitation is, again, for the user's safety. A page from `http://anysite.com` which a user has opened must not be able to access another browser tab with the URL `http://gmail.com` and steal information from there.
+- JavaScript can easily communicate over the net to the server where the current page came from. But its ability to receive data from other sites/domains is crippled. Though possible, it requires explicit agreement (expressed in HTTP headers) from the remote side. Once again, that's a safety limitation.
+>>>>>>> 6989312841d843f2350803ab552d9082437be569
 
 ![](limitations.svg)
 
@@ -128,11 +172,18 @@ zahtevajo za dodatna dovoljenja.
 Obstajajo vsaj _tri_ odlične stvari o JavaScript-u:
 
 ```compare
+<<<<<<< HEAD
 + Popolna integracija s HTML in CSS.
 + Enostavne stvari so izvedene preprosto.
 + Podpora v vseh glavnih brskalnikih, kjer je tudi samodejno omogočen.
+=======
++ Full integration with HTML/CSS.
++ Simple things are done simply.
++ Supported by all major browsers and enabled by default.
+>>>>>>> 6989312841d843f2350803ab552d9082437be569
 ```
 
+<<<<<<< HEAD
 JavaScript je edina tehnologija v brskalnikih ki omogoča vse troje hkrati in to
 naredi JavaScript unikatnega. Zaradi tega je najbolj uporabljeno orodje za
 ustvarjanje brskalniških vmesnikov.
@@ -186,3 +237,8 @@ samega JavaScript-a za dosledno razumevanje naših aplikacij.
 - Obstaja veliko programskih jezikov ki se prevedejo v JavaScript in ponujajo
   določene funkcionalnosti. Po spoznavanju JavaScript-a ja zaželjeno, da se
   spoznamo tudi s kakšnim izmed njih.
+=======
+- JavaScript was initially created as a browser-only language, but it is now used in many other environments as well.
+- Today, JavaScript has a unique position as the most widely-adopted browser language, fully integrated with HTML/CSS.
+- There are many languages that get "transpiled" to JavaScript and provide certain features. It is recommended to take a look at them, at least briefly, after mastering JavaScript.
+>>>>>>> 6989312841d843f2350803ab552d9082437be569

1-js/01-getting-started/3-code-editors/article.md

@@ -32,7 +32,6 @@ In practice, lightweight editors may have a lot of plugins including directory-l
 The following options deserve your attention:
 
 - [Atom](https://atom.io/) (cross-platform, free).
-- [Visual Studio Code](https://code.visualstudio.com/) (cross-platform, free).
 - [Sublime Text](http://www.sublimetext.com) (cross-platform, shareware).
 - [Notepad++](https://notepad-plus-plus.org/) (Windows, free).
 - [Vim](http://www.vim.org/) and [Emacs](https://www.gnu.org/software/emacs/) are also cool if you know how to use them.

1-js/01-getting-started/4-devtools/article.md

@@ -8,7 +8,7 @@ To see errors and get a lot of other useful information about scripts, "develope
 
 Most developers lean towards Chrome or Firefox for development because those browsers have the best developer tools. Other browsers also provide developer tools, sometimes with special features, but are usually playing "catch-up" to Chrome or Firefox. So most developers have a "favorite" browser and switch to others if a problem is browser-specific.
 
-Developer tools are potent, they have many features. To start, we'll learn how to open them, look at errors, and run JavaScript commands.
+Developer tools are potent; they have many features. To start, we'll learn how to open them, look at errors, and run JavaScript commands.
 
 ## Google Chrome
 

1-js/02-first-steps/02-structure/article.md

@@ -46,7 +46,7 @@ alert(3 +
 + 2);
 ```
 
-The code outputs `6` because JavaScript does not insert semicolons here. It is intuitively obvious that if the line ends with a plus `"+"`, then it is an "incomplete expression", so the semicolon is not required. And in this case that works as intended.
+The code outputs `6` because JavaScript does not insert semicolons here. It is intuitively obvious that if the line ends with a plus `"+"`, then it is an "incomplete expression", so a semicolon there would be incorrect. And in this case, that works as intended.
 
 **But there are situations where JavaScript "fails" to assume a semicolon where it is really needed.**
 
@@ -56,40 +56,36 @@ Errors which occur in such cases are quite hard to find and fix.
 If you're curious to see a concrete example of such an error, check this code out:
 
 ```js run
-[1, 2].forEach(alert)
+alert("Hello");
+
+[1, 2].forEach(alert);
 ```
 
-No need to think about the meaning of the brackets `[]` and `forEach` yet. We'll study them later. For now, just remember the result of the code: it shows `1` then `2`.
+No need to think about the meaning of the brackets `[]` and `forEach` yet. We'll study them later. For now, just remember the result of running the code: it shows `Hello`, then `1`, then `2`.
 
-Now, let's add an `alert` before the code and *not* finish it with a semicolon:
+Now let's remove the semicolon after the `alert`:
 
 ```js run no-beautify
-alert("There will be an error")
+alert("Hello")
 
-[1, 2].forEach(alert)
+[1, 2].forEach(alert);
 ```
 
-Now if we run the code, only the first `alert` is shown and then we have an error!
-
-But everything is fine again if we add a semicolon after `alert`:
-```js run
-alert("All fine now");
+The difference compared to the code above is only one character: the semicolon at the end of the first line is gone.
 
-[1, 2].forEach(alert)  
-```
+If we run this code, only the first `Hello` shows (and there's an error, you may need to open the console to see it). There are no numbers any more.
 
-Now we have the "All fine now" message followed by `1` and `2`.
+That's because JavaScript does not assume a semicolon before square brackets `[...]`. So, the code in the last example is treated as a single statement.
 
-
-The error in the no-semicolon variant occurs because JavaScript does not assume a semicolon before square brackets `[...]`.
-
-So, because the semicolon is not auto-inserted, the code in the first example is treated as a single statement. Here's how the engine sees it:
+Here's how the engine sees it:
 
 ```js run no-beautify
-alert("There will be an error")[1, 2].forEach(alert)
+alert("Hello")[1, 2].forEach(alert);
 ```
 
-But it should be two separate statements, not one. Such a merging in this case is just wrong, hence the error. This can happen in other situations.
+Looks weird, right? Such merging in this case is just wrong. We need to put a semicolon after `alert` for the code to work correctly.
+
+This can happen in other situations also.
 ````
 
 We recommend putting semicolons between statements even if they are separated by newlines. This rule is widely adopted by the community. Let's note once again -- *it is possible* to leave out semicolons most of the time. But it's safer -- especially for a beginner -- to use them.

1-js/02-first-steps/04-variables/article.md

@@ -24,7 +24,7 @@ Now, we can put some data into it by using the assignment operator `=`:
 let message;
 
 *!*
-message = 'Hello'; // store the string
+message = 'Hello'; // store the string 'Hello' in the variable named message
 */!*
 ```
 

1-js/02-first-steps/05-types/article.md

@@ -64,7 +64,7 @@ Special numeric values formally belong to the "number" type. Of course they are
 
 We'll see more about working with numbers in the chapter <info:number>.
 
-## BigInt
+## BigInt [#bigint-type]
 
 In JavaScript, the "number" type cannot represent integer values larger than <code>(2<sup>53</sup>-1)</code> (that's `9007199254740991`), or less than <code>-(2<sup>53</sup>-1)</code> for negatives. It's a technical limitation caused by their internal representation.
 

1-js/02-first-steps/08-operators/article.md

@@ -63,8 +63,8 @@ In school maths, we write that as a<sup>b</sup>.
 For instance:
 
 ```js run
-alert( 2 ** 2 ); // 2² = 4  
-alert( 2 ** 3 ); // 2³ = 8 
+alert( 2 ** 2 ); // 2² = 4
+alert( 2 ** 3 ); // 2³ = 8
 alert( 2 ** 4 ); // 2⁴ = 16
 ```
 

1-js/02-first-steps/09-comparison/article.md

@@ -7,7 +7,7 @@ In JavaScript they are written like this:
 - Greater/less than: <code>a &gt; b</code>, <code>a &lt; b</code>.
 - Greater/less than or equals: <code>a &gt;= b</code>, <code>a &lt;= b</code>.
 - Equals: `a == b`, please note the double equality sign `==` means the equality test, while a single one `a = b` means an assignment.
-- Not equals. In maths the notation is <code>&ne;</code>, but in JavaScript it's written as <code>a != b</code>.
+- Not equals: In maths the notation is <code>&ne;</code>, but in JavaScript it's written as <code>a != b</code>.
 
 In this article we'll learn more about different types of comparisons, how JavaScript makes them, including important peculiarities.
 

1-js/02-first-steps/11-logical-operators/article.md

@@ -123,7 +123,7 @@ This leads to some interesting usage compared to a "pure, classical, boolean-onl
 
     It means that `||` processes its arguments until the first truthy value is reached, and then the value is returned immediately, without even touching the other argument.
 
-    That importance of this feature becomes obvious if an operand isn't just a value, but an expression with a side effect, such as a variable assignment or a function call.
+    The importance of this feature becomes obvious if an operand isn't just a value, but an expression with a side effect, such as a variable assignment or a function call.
 
     In the example below, only the second message is printed:
 

1-js/02-first-steps/13-while-for/article.md

@@ -106,7 +106,7 @@ Let's examine the `for` statement part-by-part:
 
 | part  |          |                                                                            |
 |-------|----------|----------------------------------------------------------------------------|
-| begin | `i = 0`    | Executes once upon entering the loop.                                      |
+| begin | `let i = 0`    | Executes once upon entering the loop.                                      |
 | condition | `i < 3`| Checked before every loop iteration. If false, the loop stops.              |
 | body | `alert(i)`| Runs again and again while the condition is truthy.                         |
 | step| `i++`      | Executes after the body on each iteration. |
@@ -377,7 +377,7 @@ label: {
 }
 ```
 
-...Although, 99.9% of the time `break` used is inside loops, as we've seen in the examples above.
+...Although, 99.9% of the time `break` is used inside loops, as we've seen in the examples above.
 
 A `continue` is only possible from inside a loop.
 ````