Explore Javascript Essential Things you should know

Primitive Types

In Javascript programming , A primitive types that very important thing.

In Javascript , Primitive ( primitive values, primitive data ) . And Types and Data thatIs not object .There Are 7 primitive data types : string, number, bigint, boolean, undefined, symbol and null. All types are are immutable values.

string type : string type is represent by textual data . that is immutable.Each element in the String occupies a position in the String

number type : Number type is represent by number or integer values.

boolean : Boolean represents a logical entity and can have two values: true and false

Undefined type : A variable that has not been assigned a value undefined .

Null : Null type exactly is one values represent Null.

Try-Catch ( Error Handling method in Javascript )

Javascript programming in try-catch is most important thing for data data fetching, data excuted. now try is that means represent by block statement success excuted. and catch data some error showing then excuted by catch block statement.

The try — catch statement marks a block of statements to try and specifies a response should an exception be throw

Javascript Hoisting.

Javascript hoisting that means when we are javascript variable declaration how to to variable deal and excuted this is hoisiting.

Hoisting is a JavaScript mechanism where variables and function declarations are moved to the top of their scope before code execution.

In JavaScript, an undeclared variable is assigned the value undefined at execution and is also of type undefined.

Spread Operator.

Spread operator allows an iterable to expand in places where zero or more arguments (for function calls) or elements (for array literals) are expected. It is mostly used in the variable array where there is more than 1 values are expected. It allows us the privilege to obtain a list of parameters from an array.

Arrow Function

Javascript Arrow function introduce in ES6. It Is Shorter function expression then traditionally function expression. And it is very simplest function expression.

when you are a arrow function define you want to just one value return ,

just you can remove the return keyword and brackets .

example the below:

Event loop.

The event loop is the secret behind JavaScript’s asynchronous programming. JS executes all operations on a single thread, non-blocking but using a few smart data structures, it gives us the illusion of multi-threading.

JavaScript has a concurrency model that is based on an event loop.

Heap — Objects are allocated in a heap, a heap denotes our memory.

Stack — The stack represents the single thread provided for the JS code execution.

Web APIs — These are built in browser functions that get sent off to different threads to process

Message Queue — After the Web API’s have completed, they get sent to the message queue to await until the call stack is empty.

Cross browser testing

Cross browser testing is important thing as a web developer. because people using different browser . and every browser different capabalities. so when create web app you must testing all device and all browser just on working them.