Syntax

Quick reference

• 00:05 Okay, before we dive in and start learning hardcore JavaScript,
• 00:08 I wanna take just a couple of minutes and talk about syntax.
• 00:11 And syntax is basically the rules of how to write your computer code.
• 00:14 What does the code look like?
• 00:15 What are the different ways you do things?
• 00:18 So every programming language has its own rules.
• 00:20 This one uses colons at the end of every line.
• 00:23 This one uses semicolons at the end of every line.
• 00:25 This one uses commas at the end of every other line.
• 00:28 They're all different.
• 00:28 They all do things slightly differently and JavaScript is no difference.
• 00:31 So I wanna spend just a minute or
• 00:33 two talking about some of the most common syntax rules.
• 00:36 Now, you're gonna pick this stuff up as we move along, but here at the beginning,
• 00:40 I just wanna give a few very obvious ones and
• 00:43 spend just a couple of minutes talking about it.
• 00:44 So first of all, whenever we write a line of code in JavaScript,
• 00:48 it's called a statement, we're writing a statement of something.
• 00:50 And all statements end in semicolons, so
• 00:53 we have this script.js file earlier we could see, this ended in a semi-colon.
• 00:59 Every single statement you write in JavaScript will end in semi-colons.
• 01:02 So just burn that into your brain, you're always going to end in semi-colons.
• 01:06 And you're gonna forget from time to time.
• 01:07 You're gonna be writing code, and
• 01:08 you're gonna forget to put that semi-colon on the end, and it's not gonna work, and
• 01:12 you're gonna go, why isn't my code working?
• 01:14 You forgot the semicolon, happens all the time,
• 01:16 happens to me even after 20 years of doing this.
• 01:18 So that's the first thing.
• 01:20 Next, variables.
• 01:22 A variable, we haven't talked about, obviously.
• 01:23 We'll talk about variables later.
• 01:25 But variables, you call them like say,
• 01:29 myvariable equals something, whatever, right?
• 01:35 So how you name that variable in JavaScript ... First of all,
• 01:38 JavaScript is case sensitive.
• 01:40 And that means, for instance, we copy this and paste another copy.
• 01:46 So we have MyVariable, these are two very different variables, right?
• 01:50 Because this one has capital M and a capital V, and this one doesn't.
• 01:54 So JavaScript sees these as two different variables.
• 01:56 Some programming languages are case-insensitive,
• 01:59 where this would be the same variable.
• 02:01 Not JavaScript.
• 02:02 Capital letters and lowercase letters are very important in JavaScript.
• 02:05 So in JavaScript, the convention is to use something called camel case.
• 02:10 And this second one is camel case.
• 02:12 It has a capital M and a capital V, and they call it c camel case,
• 02:15 because camels have humps, a couple of humps.
• 02:18 And so, this capital M is a hump, and this capital V is a hump, that's camel case.
• 02:24 So in JavaScript, the convention is to use camel case, but to use a lowercase for
• 02:29 the first word, so lowercase my, uppercase variable.
• 02:33 That's how you do it in Javascript.
• 02:34 Now, this is valid too.
• 02:36 You can use an underscore to separate words in Javascript.
• 02:39 Most people just don't do that, though.
• 02:41 Sorta like the community of coders have decided that this is the way to do it,
• 02:45 lowercase camel case.
• 02:46 Some people like to do dashes with their variables.
• 02:49 You can't do a dash like that in JavaScript 'cause JavaScript sees that as
• 02:54 subtraction.
• 02:55 This is a subtraction sign in JavaScript, so it
• 02:57 thinks you're trying to subtract variable from my and it throws up an error.
• 03:02 So that's basically it for variables.
• 03:04 Next, strings.
• 03:06 This is a string here, this something right here.
• 03:09 We've created it with double quotation marks, right?
• 03:12 In JavaScript, you can use double quotation marks or you can
• 03:17 use single quotation marks like this, and it's the same thing.
• 03:23 So this something is the same as this something.
• 03:26 Double quotation marks versus single quotation marks, perfectly normal.
• 03:30 And there are instances where you might wanna use single quotation marks or
• 03:33 double quotation marks.
• 03:34 An we'll get into that as we go along and
• 03:35 you'll start to learn about different things like that.
• 03:38 So those are sorta the big, obvious syntax rules in JavaScript.
• 03:42 Like I said there's a bunch of other ones.
• 03:43 You'll pick them up as we go along and
• 03:44 I'll point them out from time to time as we move through this course, but
• 03:48 those are the ones to keep an eye on right off the bat.
• 03:51 This semi colon is the big one.
• 03:53 So in the next video I wanna talk about JavaScript output.

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