Question

Teaching Some Code (JavaScript: Variables, Constants, Functions, Datatypes)

Answer 1

This time around, I'm going to be helping with JavaScript.

Answer 2

If your using chrome, you can run the code discussed in this thread in your console by hitting `ctrl+shift+j`

Answer 3

Let's start with something simple, Variables.
A variable is something that stores data and can be changed later.

You can define a variable by doing something like the following:
```
var a = "text";
```
This will define the variable "a" with the value of "text"

if you were to type in the console "a" after running this snippet of code, it would return "text" as seen in the attachment

Answer 4

Does that makes sense so far?

Answer 5

Yes sir :P

Answer 6

Yesh. e.e

Answer 7

Alright, you guys try now, define a variable and call it

Answer 8

Can't I'm on mobile x.x

Answer 9

Oh, something I forgot to mention. Syntax.
at the end of each code line you want to have a `;`, that declares the end of the line. It's not required in JavaScript, but it's very good to know and a good practice to follow.

Answer 10

```
var b = "test";
```

Answer 11

Like that? o:

Answer 12

Indeed. Now then, constants.

Similar to variables a constant stores data, however a constant cannot be changed after being defined

You can define a constant by using `const` in place of `var`.

Attempting to change a constant after being defined will result in a error, which you can see in the attachment.

Answer 13

Make sense?

Answer 14

Yes.

Answer 15

(code used in above example)
```
const example = "Hello World!";
example = "Example";
```

Answer 16

You can never change a constant? o:

Answer 17

Nope

Answer 18

It does :P

Answer 19

Is it necessary to include `example = "Example";` ?

Answer 20

No, that was just to show that it would throw a error attempting to change the value

Answer 21

Ooooooo

```
const example = "test";
```

Answer 22

Correct?

Answer 23

Indeed.

Answer 24

Now let's talk about the different datatypes that one can pass to a variable.
The main ones are as follows:
Integers: Numbers, such as 5 or 292
Strings: Text, such as "testing"
Objects: More on this later, it is essential a key -> value data store such as `{"a":"b"}`
Arrays: More on this later, Multiple values in the same string, example would be `["test",1,{"a":"b"}]`

Answer 25

```
["testing",5,{"b":"c"}]
```
e.e

Answer 26

Arrays aren't just limited to that by the way
They can be something like this:
```
["test","example","dog"]
```

Or something much more complex combining all other data types into one.

Answer 27

Make sense?

Answer 28

Yes I get it ;P

Answer 29

How do you combine all the other data types in one? e.e

Answer 30

The first example I gave, gave a example of that. We'll get more into that later

Answer 31

Does this all make sense so far dude?

Answer 32

Yes, though `ctrl+shft+j` doesn't work for me

Answer 33

Because you're on mac. It's `cmd+opt+j` on mac

Answer 34

Now let's talk about a comment
A comment is something that can be written down in the code, but won't execute.

A single line comment is done with `//`
A multi line comment starts with `/*` and ends with `*/`

Answer 35

In some languages, a single line comment is `#` (pointing that out incase anyone looks at other languages)

Answer 36

Make sense so far?

Answer 37

HeydontmentionotherlanguagesweareonlytalkingaboutJavaScript,itcangetconfusingsometimes at least for me

Answer 38

Noted

Answer 39

What about you @Elsa213

Answer 40

K elsa died, moving on

Answer 41

Next let's do functions.
```
function function_name() {
//code goes here
}
```
That is the basic syntax for functions.
You can run what's in a function by calling it

Calling something refers to running it's name
For a variable you would run it's name, however for a function, you would run it's name with ()
for example, in this instance we would call our function with `function_name()`

Make sense so far?

Answer 42

What kind of function :P

Answer 43

If the name is longer than a word does it use underscores as spaces?

Answer 44

Correct, or you can just capitalize the next word likeThis

Answer 45

Now lets talk about how you can pass data to a function, and return data from a function

You can pass data to a function by defining a variable with the function within the parenthesis.

You can return data by using the `return` keyword. This also stops execution of the function any further.

As a example:
```
function example(hello) {
return hello;
}
```
This will return whatever is passed to the first variable of the function.

Passing data to the function when running it is done by having that data in the parenthesis when running it
```
function example(hello) {
return hello;
}
example("Hello World!");
```
This example will return "Hello World!" to the console.

Still with me?

Answer 46

Yes :P

Answer 47

Yup

Answer 48

You can pass multiple parameters to functions by separating each value with a ","
for example...
```
function example(hello,world) {
return hello+world;
}
example("Hello","World");
```

the `+` in this example combines the 2 variables together, and then the `return` outputs them.

Make sense?

Answer 49

Yes :D

Answer 50

Dude you still with me?

Answer 51

Yes x'D

Answer 52

Alright, next let's do a assignment to make sure you guys were paying attention =P

I want you to construct a small script, that defines a variable, and a constant, as well as a function.

That function should be declared accepting 2 parameters, outputting them both.

You should then pass the variable and constant you declared before the function to the function.

Answer 53

Judging by the fact that it's been 20 minutes, and it took me 15 seconds to write what I described above (although I expected it would take a maximum of ~5 minutes), I assume you're all struggling on this?

Answer 54

So I can define a variable, constant but having troubles with functions

Answer 55

Let me see what you got and I can explain what went wrong ^_^

Answer 56

I already defined dood

Answer 57

You're telling the function to return itself, not the variable you defined in the function scope "testing"

Answer 58

oh, well then

Answer 59

How would I fix that?

Answer 60

change the return line to
```
return dood+testing
```

Answer 61

Ohh okay I see

The `+` doesn't put a space?

Answer 62

No, just combines the two variables.

Answer 63

It also adds if you have 2 integers
I.E.
```
var a = 42;
var b = 91;
var c = a + b;
```

Answer 64

I've tried that before ;o

Answer 65

@Elsa213 Are you following so far? =P

Answer 66

Should I reveal the answer, or do you have it now dude?

Answer 67

Should I reveal the answer?

Answer 68

wait answer? o-o

Answer 69

the answer to the assignment I gave...

Answer 70

Oh well I guess I was the only one that did the hw ¯\_(ツ)_/¯

Answer 71

(it's pretty freeform, but in the end still gets the same result)

Answer 72

NO IM GERE

Answer 73

How do you type the code out with colors?

Answer 74

\```javascript
code here
\```

Answer 75

Ah like discord x'D

Answer 76

I mean, technically discord is like us, even OS had it like that long before discord was even a thought lol

Answer 77

Shall we move on?

Answer 78

Or are you still catching up TGP?

Answer 79

Catching up, one second

Answer 80

Okie, I copied and pasted the steps in the colors of red and purple. Purple = important. Red = very important. Got it

Answer 81

You said you were going to try to do the assignment?

Answer 82

Yes sir

Answer 83

waits

Answer 84

I don't get where to put the variable at :|

Answer 85

You define the variable before the function

Answer 86

do i remove everything? o-o

Answer 87

(or after, doesn't really matter so long as it's defined before it's used)

Answer 88

What do you mean do you remove everything? O_o

What do you have so far?

Answer 89

that part

Answer 90

Don't worry about that, it has nothing to do with any code you were doing x'D

Answer 91

Oops LOL

Answer 92

wut to do for the code thingy

Answer 93

hrmmm



uhhh like dis?

Answer 94

spelled celestial wrong >.>

Answer 95

How ._.

Answer 96

Yes, however you forgot one part, you were supposed to pass a variable to the function (by defining the variable before using it)

Answer 97

hrmmm

Answer 98

Bg how'd you do that

Answer 99

im confused e.e

Answer 100

Alright, let me give you example

Answer 101

```
var hello_world = "Hello World!";
function return_var(value) {
return value;
}
return_var(hello_world);
```
Output is "Hello World!"

Get it now?

Answer 102

*hits head on desk repeatly*

Answer 103

i think so e.e

Answer 104

Alright, try it =P

Answer 105

TGP where are you stuck?

Answer 106

Where to type it in 😂

Answer 107

The chrome console

Answer 108

You had it there

Answer 109

OHHH

Answer 110

so like dis?


hrmmmm

Answer 111

honestly im still confused >.>

Answer 112

Back, had to eat dinner.

You did it correctly, now split it into 2 variables (1 of them a constant)

Answer 113

@563blackghost

Answer 114

hrmmmm e.e

Answer 115

Should I show you the solution?

Answer 116

let meh try one more time, then put it okie?

Answer 117

Kk

Answer 118

what do you mean by split to two variables?

i add another besides star? (in my case dat is)

Answer 119

How come when you define a variable, you get returned with "undefined"

Answer 120

Because you didn't specify anything to be returned, so since nothing returns, the return is undefined shadow

Answer 121

I mean have 2 variables like you did in your first attempt, but using variables instead (and one of those variables using the `const` prefix)

Answer 122

(as in predefined BOTH values you pass to the function)

Answer 123

Can you define multiple variables in the same line?

Answer 124

Yes, like this
```javascript
var example="a",test=2,extra="testing";
```
Put a comma inbetween each variable you want to define.
You can also define variables without a value until your ready for a value like this:
```javascript
var example,test,extra;
var example = "a";
var test = 2;
var extra = "testing";
```

Answer 125

i dont get it ultri ;-; i understand adding the var but i dont know how to add da consts ;-;

its const example = "test"; right?

Answer 126

Correct

Answer 127

BTW you might want to put code like this: \`code here\`

Answer 128

```javascript
const people = "something"
var ghost = "boo"
```

Answer 129

```javascript
const vara = "Hello";
var varb = "World!";
function demo(a,b) {
return a+b;
}
demo(vara,varb);
```
Alright, here's how it should look =P

Answer 130

O-O

Answer 131

oh

Answer 132

I read coordinate points.

Answer 133

*taking note*

Answer 134

[\begin{ var a = "a";} \]

Answer 135

How do you make a block of code * '^' *

Answer 136

Okay look @mhchen

Answer 137

do

Answer 138

No do this

```

Answer 139

```
words under it

Answer 140

```
test
```
see?

Answer 141

Normal Text
```
var code = "Codey Text";

```

Normal text

Answer 142

Yesh I got it. Can't wait for Ultri's next javascript tutorials.

Answer 143

```
test
```
```
test
```
```
test
```
```
test
```
```
test
```
```
test
```
And the boxes can be repeated and repeated as shown ^

Answer 144

could you teach me the code of the jedi and the code to be mod?

Answer 145

Second post is here: https://questioncove.com/study#/updates/5ac2953e7ea699a0284b8800