Forem: ana

Return an element in console

ana — Thu, 04 May 2023 17:13:17 +0000

Do you want see an element that you create in your HTML on console by JS?

It's so easy and simple.
there is no more explain about this, but you should know some small tips about it:

We can do this with using from getElementById() method.
this return one element with specified ID.
you should remember that: your IDs name should be unique.
and you should use "variables name rule" for your IDs name.

Here our answer:

select an element with this method like that:

document.getElementById("demo");

This would return the full HTML element:

<h1 id="demo">Hello world.</h1>

We should write our method in console.log as we know for see it in console:

console.log(document.getElementById("demo"));

Finally, I must mention, these things I said are about "HtmlDom" topic in JS.

javaScript Class

ana — Fri, 03 Mar 2023 12:41:09 +0000

In this article I just want explain a little about class topic in java script.
As you know Class its a concept that you can see in any programming language.
letsGo...
In first I show you syntax of class:

class ClassName{
constructor(){...}
}

Tip/ normally we write class name with capital letter.

Here there is 1 question! what is constructor?
actually the constructor is a place that we declare all variable we want use in our class, in every function we make it later, for example:

class Human{
constructor(name, lName, age){
this.name = name;
this.lName = lName; 
this.age = age;
}
...
}

as you can see in above codes I declare All variables in constructor. just for you know, the constructor in JS is __init__ in python.

well it doesn't matter. anyway, after make your constructor maybe you want to use from those in your functions..
if I want show this in example:

class Human{
constructor(name, lName, age){
this.name = name;
this.lName = lName; 
this.age = age;
}
showName(){
console.log(this.name + " " + this.lName);
}
}

Tip1/ showName is a function.
Tip2/ this keyword refers to variable we declare in our class and you should use from that.

so How can we use from our Class?

const VariableName = new ClassName(parameter1, parameter2,...)

in example:

const person1  = new Human("Ana", "am", "19");

Tip1/ order for declare value is important. if i Write "19" at the first that value it will equal to name.

How can we use from our Function? (showName)

person1.showName();

I should tell you, in this subject(class) there are so many tips. and you should care about this and learn more about it. I just explained the class topic in really short form.

Don't forget practice.

java script Hoisting

ana — Fri, 24 Feb 2023 09:39:01 +0000

HI!
in this article i want explain Hoist and Hoisting rule in java script. as you know javaScript its a language with a lot concept and rules and tips. so Hoisting its another rule of variable in javaScript, so important and for your programming way it can be so good and helpful.

Hoisting is about Declaration and this things.
there is some way for declare and use and display a variable and value of that variable.
for example:

x = 1;
console.log(x);
var x;

maybe after this you say with yourself main rule for declare a variable is this:

var x = 1;

yes, in general we declare with this rule and syntax but if we use from those syntax we use from Hoist rule in our program.
but believe me Hoist its can be useful and helpful, every rules in javaScript is so helpful and good for our way.

Tip/ we can't use const or let keyword for above example, this will result in a ReferenceError.

if_else in java script:

ana — Thu, 23 Feb 2023 14:26:26 +0000

in this article i want explain some Tip about if and else.
in javaScript and also in another programming languages, the name of this topic is : Conditional Statements.
Im sure that you see this topic in your programming way in any language you work with it..
so you should know we use if and else word for our usage.
anyway, at first I write the syntax of if, else, etc.

if:

if (condition) {
  //  the things we want will be done if the conditions are True.
}

else:

if (condition) {
  //  the things we want will be done if the conditions are True.
} else {
  //  the things we want will be done if the conditions are False.
}

else if:

if (condition1) {
  //  the things we want will be done if the condition1 is True.
} else if (condition2) {
  //  the things we want will be done if the condition1 is False.
} else {
  //  the things we want will be done if the condition1 and condition2 is False.
}

so it's done... these is all about if, else and else if.

at the end, i write a example and you write the answer in comment if you like;)

var x = 0;

if (x = 0){
console.log("I should keep going, it doesn't matter how hard is!");
}else if (x = 00){
console.log("trying it's my answer");
}else{
console.log("i should not have shame feeling about trying");
}

enjoy,byeeeeè.

Arrow Function

ana — Wed, 15 Feb 2023 18:45:02 +0000

Before explain Arrow function you should learn EcmaScript(6)
and learn about that.

So.. I just explain a little about that: is a JavaScript standard intended to ensure the interoperability of web pages across different browsers.

well, now we arrived to ArrowFunction.
as you know ecmaScript has multiple versions, in last version(5) arrowFunction was somthing like that:

const function1 = function(x, y) {
   return x * y;
}

But in the next version arrowFunction in ecmaScript changed:

const function1 =(x, y)=> x * y;

so whenever you see this symbol =()=> in javaScript its mean Arrow Function!!

this is very important topic in java script, if one day you want to learn React you need to know what is arrowFunction and how should use from it.

as you see, we declare a variable with const and gave a name to it and then after equal symbol = we gave our arguments in the parentheses and use from this =>, after this line we just return our output, remember this, it doesn't matter to use return word or not, but in React!! is so important.

JavaScript function call() method:

ana — Fri, 03 Feb 2023 15:46:12 +0000

imaging that: you have some object in your program(with JS language) and you have some name:value in your object with any data type.
if we say any data type that can be to this mean we want write a name:value and "value" be a function?
Ofcourse!!

if function situation is to be that, function take two parameters and then return their in output, and if we want specify our parameters from a another object we can use call method!

example:

const x = {
fullName: function(){
return this.name + " " + this.lName
}
};

But where is name or lName(last name)?

is here: (in another object, we take from this object)

const object1 = {
name: "ana",
lName: "amini"
}

So now we achieve to method part:

console.log(x.fullName.call(object1));

and then output will be like that:

ana amini

Tip(1): for showing a value of the name in object we use from this rule: objectName.name1;

Tip(2): we use " " in our function, so our values are separate from each other!

;)!

Array Or Object In JavaScript language.

ana — Fri, 23 Dec 2022 09:12:39 +0000

Array or Object It is a very important topic in JS.
If you want to learn javaScript in a website, youTube, book or All facilities.. there is a subject with this name => Array and object.
And something else that should be here, is difference between these two => Array and Object.
in first we should know what is Array! and then what is Object!!

before I explain, I want to tell you some resources for learn JS.

3.https://www.javascript.com/

but you should know "Books" is better than every choice for learn JS.

like "javasSript from beginner to professional" || "you don't know javaScript"

( yup, I use || for Or;) if you know..).

syntax of a Array:

There are three points here:

I use [] for write a Array.

I use any name I like for Variable.

I can use from var or let instead const.(but there is some rules for that, and usually we use const for write a Array.)

if you don't know what is var or let or maybe const, check here:

https://www.w3schools.com/js/js_variables.asp

syntax of Object:

and Object Points..:

I use{} for write a Object.

I use a variable for every item in Object.

name, age, nationality its a "key" for "value" I wrote in front of it.

well, in end remember that:
name, age, etc.. its a "key"
ana, 19, etc.. its a "value"
and we say that =>
name is a key for ana and ana its a value.
=> We say in the term (key-value).

syntax for array:

const arrayName = [value1, value2,...]

syntax for object:

const objectName = {key1 : value1, ...}

The difference between Array And Object:

now we should let's answer to that question:
what is difference between a Array and a object?

as you can see: I wrote array with [ ] and then I wrote directly value on it.

and then I wrote object with { } and write value but after key of that value.

but the main difference between a Array and Object its index of these two.

"index" its really easy and important subject and rule for array and object in JS.

in a Array every value from first have a index and that index start with 0, and then 1 and then 2 and...n. you should know we can't change that rule for Array. but in object:

in a Object every value from first have index but that index is what we call, for example for "ana" I give "name" for index of this value.
for another value I give index I want, after that in our program we wrote and we have Object
every value in Object have index and that index its "key" we wrote for value.

summery:

index of array start with 0,1,2,...:

const array1 = ["a", "b"]

=> index of "a" its: 0
=> index of "b" its: 1

index of object start with key1, key2,..:

const object1 = {name: "ana", age:"19"}

=> index of "ana" its name
=> index of "19" its age

forgive me if I forget semicolon :)

The end.