Ten important topics of javascript you have to know

In this tutorial, we are going to talk about 10 important topics which you should know. Let’s begin.

1) The first topic of this tutorial is API. Now you may ask, what is an api? And what is the functionality of an api?

Ans: API stands for (application programming interface). But now, your question is what does this mean? I won’t tell you here the typical definition of API. Instead of this, I’ll try to explain its real-life use case.

In our real-life use case api is nothing but a specific URL or address using this you can connect with other applications and load your desired data from the connected application that’s it.

2) The second topic of this tutorial is api get and post request. What is the api get and post request?

Ans: When we want to load data from an api and show it to the interface, we have to send a get request through the server to the api and after that, if our request gets succeed it will respond with our desired data. This is called API GET REQUEST.

Besides this, when we want to send data from our client-side to a specific api, we have to send a post request through the server to the api. And similarly, if our request gets succeed it will respond with a success message.

3) The third topic of this tutorial is JSON. Now the question is what is JSON? And what can we do with this?

Ans: JSON stands for (javascript object notation). This is specially formatted data and using this formatted data, we can easily put it in the database. Look at the following example, this is JSON formatted data.

{“id”: 1, “name”: “sakib”}

And there are two methods to work with this specially formatted data. The first one is JSON.stringify(). Using this method we can convert normal formatted data to JSON type. And the second method is, JSON.parse() using this method we can parse or convert JSON formatted data to normal type data. In the following text, I tried to give an example.


var myObj = { name: “John”, age: 31, city: “New York” };

var myJSON = JSON.stringify(myObj);console.log(myJSON)

//expected result is {“name”:”John”,”age”:31,”city”:”New York”}

var myJSON = ‘{“name”:”John”, “age”:31, “city”:”New York”}’;

var myObj = JSON.parse(myJSON); console.log(myObj)

//expected result is {name: “John”, age: 31, city: “New York”}

4) The fourth topic is truthy and falsy value. What is truthy and falsy value?

Ans: This kind of value in javascript is called boolean value. All values are truthy unless they are defined as falsy. These are the falsy values ( false , 0 , “” , null , undefined , and NaN ) except these all are the truthy values.

5) The fifth topic is null vs undefined.

Ans: Null and Undefined are both data types in JavaScript.Undefined is a variable that has been declared but not assigned a value.

Null as an assignment value. So you can assign the value null to any variable which basically means it’s blank.

6) The sixth topic is double equal (==) vs triple equal (===).

Ans: The double equal and the triple equal both are equality comparison operators in JavaScript. The double equal is used to check only the value. And the triple equal is used to check both value and data type.