Skip to main content

ES 6: Different between REST and SPREAD Operators

Java-Script Rest and Spread Operators: 

In JavaScript, we are using three dots ( ... ) for both REST and SPREAD Operators. But these two operators are not the same they both have a different purpose.




REST Operator

- Purpose of this operator is to collect all remaining elements into the array.
- For Example: 
 
      - let take one array in below example

 

   - O/P :
      Necklace
[ 'Earring', 'Payal', 'Brooch', 'Bangles']


  - In the Above example three-dot contain the rest of the product time in the restProdcut variable that calls Destructuring that breaks our code into small pieces.

  - so in the above example, mainProduct variable contains my Main product and restProduct varibale contains my rest products.

  - The rest operator always gives rest data into array format only.

  - while creating function we can also use rest operator like below




SPREAD Operator:

 - It's work opposite to rest operators, like in rest operator we are collecting item into an array but in spread operator we are unpack the collected items into a single elements.

 - For Examples

   


  - O/P : [ 'Necklace', 'Earring', 'Payal', 'Brooch', 'Bangles'];
  
 - We can say SPREAD operator is used for copy one array into another array or concatenates.



I hope you guys enjoyed this tutorial 😼

Comments

Popular posts from this blog

Different between ``===`` and ``==`` operators in JavaScript

Hello Guys, In this blog we are going to learn about "===" and "==" different with details understanding and examples. JavaScript operators that you might have stumbled upon as a developer include "===", "==". JavaScript's "==" operator is commonly utilized for loose comparison purposes.  It functions by converting both of the values to a common type and then comparing them for equality.  Here's an example: The comparison operator "==" transforms the value of "17" from a string to a number before determining if the values match.  Consequently, if both versions of the data share the same properties and values, the comparison is marked as valid and returns true. The results of the "==" operator can occasionally be surprising, including: The comparison returns true when the "==" operator converts the empty string to the number 0 and compares it to the number 0.  This can result in bugs, so ...

Configure and Build Angular application for different environments like QA and Staging

 Generally in the angular application by default, we have two environment  1) Development  2) Production Environment.  But In some cases, we need to add other environments for our application like QA and staging environment.  So let's see how we can add multiple environments in angular application for that we have to perform some steps.  Step 1:- Custom Environment File - Here For every target environment, we have to create a new file under  the environment folder  here i have created two files  evnironment.qa.ts  and  environment.staging.ts Step 2:- Custom Environment Setting - Here now you have to configure your  environment name  and new environment API URL and other settings For Example:- Step 3:- Need to Update the angular.json file - Now in the angular project you can find  the angular.json  file. in that file, you have to configure your new environment like below Here I have configure for QA environment St...

What is CanActivateChild() Method in angular routes with details understanding and examples

Hello Guys, In this blog we are going to learn about child routes using auth guard with CanActivateChild() with details understanding and examples. CanActivateChild()  allows you to guard child routes in a similar way to  CanActivate  for guarding individual routes. CanActivateChild() is basically used to protect child routes inside the application from unauthorized users. This means if users don't have access then they can't access child routes. When every you creating canActivateChild, in that we are creating guards that execute before access of child routes. CanActivateChild() method normally takes two parameters : route and state. The route parameter represents the child route being activated, while the state parameter represents the current router state. The CanActivateChild() method must return a boolean value indicating whether the user has permission to access the child method. For Examples :    Authenticating users with a service named authServ...