3 Ways to Clone Objects in JavaScript

3 Ways to Clone Objects in JavaScript

Because objects in JavaScript are references values, you can't simply just copy using the =. But no worries, here are 3 ways for you to clone an object

Because objects in #JavaScript are references values, you can't simply just copy using the =. But no worries, here are 3 ways for you to clone an object 👍

const food = { beef: '🥩', bacon: '🥓' }

 

 

// "Spread"

{ ...food }

 

 

// "Object.assign"

Object.assign({}, food)

 

 

// "JSON"

JSON.parse(JSON.stringify(food))

 

// RESULT:

// { beef: '🥩', bacon: '🥓' }

Objects are Reference Types

Your first question might be, whey can't I use =. Let's see what happens if we do that:

const obj = {one: 1, two: 2};
 
const obj2 = obj;
 
console.log(
  obj,  // {one: 1, two: 2};
  obj2  // {one: 1, two: 2};
)

So far, both object seems to output the same thing. So no problem, right. But let's see what happens if we edit our second object:

const obj2.three = 3;
 
console.log(obj2);
// {one: 1, two: 2, three: 3}; <-- ✅
 
console.log(obj);
// {one: 1, two: 2, three: 3}; <-- 😱

WTH?! I changed obj2 but why was obj also affected. That's because Objects are reference types. So when you use =, it copied the pointer to the memory space it occupies. Reference types don't hold values, they are a pointer to the value in memory.

If you want to learn more about this, check out Gordon's Zhu Watch and Code course. It's free to enroll and watch the video "Comparison with objects". He gives a super awesome explanation on it.

1. Using Spread

Using spread will clone your object. Note this will be a shallow copy. As of this post, the spread operator for cloning objects is in Stage 4. So it's not officially in the specifications yet. So if you were to use this, you would need to compile it with Babel (or something similar).

const food = { beef: '🥩', bacon: '🥓' };
 
const cloneFood = { ...food };
 
console.log(cloneFood);
// { beef: '🥩', bacon: '🥓' }

2. Using Object.assign

Alternatively, Object.assign is in the official released and also create a shallow copy of the object.

const food = { beef: '🥩', bacon: '🥓' };
 
const cloneFood = Object.assign({}, food);
 
console.log(cloneFood);
// { beef: '🥩', bacon: '🥓' }

3. Using JSON

This final way will give you a deep copy. Now I will mention, this is a quick and dirty way of deep cloning an object. For a more robust solution, I would recommend using something like lodash

const food = { beef: '🥩', bacon: '🥓' };
 
const cloneFood = JSON.parse(JSON.stringify(food))
 
console.log(cloneFood);
// { beef: '🥩', bacon: '🥓' }

Lodash DeepClone vs JSON

Here's a comment from the community. Yes, it was for my previous post, How to Deep Clone an Array. But the idea still applies to objects.

Alfredo Salzillo: I'd like you to note that there are some differences between deepClone and JSON.stringify/parse.

  • JSON.stringify/parse only work with Number and String and Object literal without function or Symbol properties.
  • deepClone work with all types, function and Symbol are copied by reference.

Here's an example:

const lodashClonedeep = require("lodash.clonedeep");
 
const arrOfFunction = [() => 2, {
    test: () => 3,
}, Symbol('4')];
 
// deepClone copy by refence function and Symbol
console.log(lodashClonedeep(arrOfFunction));
// JSON replace function with null and function in object with undefined
console.log(JSON.parse(JSON.stringify(arrOfFunction)));
 
// function and symbol are copied by reference in deepClone
console.log(lodashClonedeep(arrOfFunction)[0] === lodashClonedeep(arrOfFunction)[0]);
console.log(lodashClonedeep(arrOfFunction)[2] === lodashClonedeep(arrOfFunction)[2]);

@OlegVaraksin: The JSON method has troubles with circular dependencies. Furthermore, the order of properties in the cloned object may be different.

Shallow Clone vs Deep Clone

When I used spread ... to copy an object, I'm only creating a shallow copy. If the array is nested or multi-dimensional, it won't work. Here's our example we will be using:

const nestedObject = {
  country: '🇨🇦',
  {
    city: 'vancouver'
  }
};

Shallow Copy

Let's clone our object using spread:

const shallowClone = { ...nestedObject };
 
// Changed our cloned object
clonedNestedObject.country = '🇹🇼'
clonedNestedObject.country.city = 'taipei';

So we changed our cloned object by changing the city. Let's see the output.

console.log(shallowClone);
// {country: '🇹🇼', {city: 'taipei'}} <-- ✅
 
console.log(nestedObject);
// {country: '🇨🇦', {city: 'taipei'}} <-- 😱

A shallow copy means the first level is copied, deeper levels are referenced.

Deep Copy

Let's take the same example but applying a deep copy using "JSON"

const deepClone = JSON.parse(JSON.stringify(nestedObject));
 
console.log(deepClone);
// {country: '🇹🇼', {city: 'taipei'}} <-- ✅
 
console.log(nestedObject);
// {country: '🇨🇦', {city: 'vancouver'}} <-- ✅

As you can see, the deep copy is a true copy for nested objects. Often time shallow copy is good enough, you don't really need a deep copy. It's like a nail gun vs a hammer. Most of the time the hammer is perfectly fine. Using a nail gun for some small arts and craft is often case an overkill, a hammer is just fine. It's all about using the right tool for the right job 🤓

Performance

Unfortunately, I can't write a test for spread because it's not officially in the spec yet. Nevertheless, I included it in the test so you can run it in the future 😝. But the result shows Object.assign is a lot faster than JSON.

Performance Test

Community Input

Object.assign vs Spread

@d9el: It's important to note that Object.assign is a function which modifies and returns the target object. In Samantha's example using the following,

const cloneFood = Object.assign({}, food) 

{} is the object that is modified. The target object is not referenced by any variable at that point, but because Object.assign returns the target object, we are able to store the resulting assigned object into the cloneFood variable. We could switch our example up and use the following:

const food = { beef: '🌽', bacon: '🥓' };
 
Object.assign(food, { beef: '🥩' });
 
console.log(food);
// { beef: '🥩', bacon: '🥓' }

Obviously, the value of beef in our food object is wrong, so we can assign the correct value of beef using Object.assign. We aren't actually using the returned value of the function at all, but we are modifying our target object which we have referenced with the const food.

Spread on the other hand is an operator which copies properties of one object into a new object. If we wanted to replicate the above example using spread to modify our variable food...

const food = { beef: '🌽', bacon: '🥓' };
 
food = {
  ...food,
  beef: '🥩',
}
// TypeError: invalid assignment to const `food'

... we get an error, because we use spread when creating new objects, and therefore are assigning a whole new object to food which was declared with const, which is illegal. So we can either choose to declare a new variable to hold our new object in, like the following:

const food = { beef: '🌽', bacon: '🥓' };
 
const newFood = {
  ...food,
  beef: '🥩',
}
 
console.log(newFood);
// { beef: '🥩', bacon: '🥓' }

or we could declare food with let or var which would allow us to assign a whole new object:

let food = { beef: '🌽', bacon: '🥓' };
 
food = {
  ...food,
  beef: '🥩',
}
 
console.log(food);
// { beef: '🥩', bacon: '🥓' }

Thanks: @d9el

Deep Clone using External Libraries

  • @lesjeuxdebebel: Personally I use jquery with $.extend(); function
  • @edlinkiii: underscore.js ~~ _.clone()
  • @Percy_Burton: The only way I've known to do this is with the Lodash library, cloneDeep method.

More Ways using JavaScript

  • @hariharan_d3v: Object.fromEntries(Object.entries(food)) [shallow] clones the object.

JavaScript Tutorial: if-else Statement in JavaScript

JavaScript Tutorial: if-else Statement in JavaScript

This JavaScript tutorial is a step by step guide on JavaScript If Else Statements. Learn how to use If Else in javascript and also JavaScript If Else Statements. if-else Statement in JavaScript. JavaScript's conditional statements: if; if-else; nested-if; if-else-if. These statements allow you to control the flow of your program's execution based upon conditions known only during run time.

Decision Making in programming is similar to decision making in real life. In programming also we face some situations where we want a certain block of code to be executed when some condition is fulfilled.
A programming language uses control statements to control the flow of execution of the program based on certain conditions. These are used to cause the flow of execution to advance and branch based on changes to the state of a program.

JavaScript’s conditional statements:

  • if
  • if-else
  • nested-if
  • if-else-if

These statements allow you to control the flow of your program’s execution based upon conditions known only during run time.

  • if: if statement is the most simple decision making statement. It is used to decide whether a certain statement or block of statements will be executed or not i.e if a certain condition is true then a block of statement is executed otherwise not.
    Syntax:
if(condition) 
{
   // Statements to execute if
   // condition is true
}

Here, condition after evaluation will be either true or false. if statement accepts boolean values – if the value is true then it will execute the block of statements under it.
If we do not provide the curly braces ‘{‘ and ‘}’ after if( condition ) then by default if statement will consider the immediate one statement to be inside its block. For example,

if(condition)
   statement1;
   statement2;

// Here if the condition is true, if block 
// will consider only statement1 to be inside 
// its block.

Flow chart:

Example:

<script type = "text/javaScript"> 

// JavaScript program to illustrate If statement 

var i = 10; 

if (i > 15) 
document.write("10 is less than 15"); 

// This statement will be executed 
// as if considers one statement by default 
document.write("I am Not in if"); 

< /script> 

Output:

I am Not in if
  • if-else: The if statement alone tells us that if a condition is true it will execute a block of statements and if the condition is false it won’t. But what if we want to do something else if the condition is false. Here comes the else statement. We can use the else statement with if statement to execute a block of code when the condition is false.
    Syntax:
if (condition)
{
    // Executes this block if
    // condition is true
}
else
{
    // Executes this block if
    // condition is false
}


Example:

<script type = "text/javaScript"> 

// JavaScript program to illustrate If-else statement 

var i = 10; 

if (i < 15) 
document.write("10 is less than 15"); 
else
document.write("I am Not in if"); 

< /script> 

Output:

i is smaller than 15
  • nested-if A nested if is an if statement that is the target of another if or else. Nested if statements means an if statement inside an if statement. Yes, JavaScript allows us to nest if statements within if statements. i.e, we can place an if statement inside another if statement.
    Syntax:
if (condition1) 
{
   // Executes when condition1 is true
   if (condition2) 
   {
      // Executes when condition2 is true
   }
}

Example:

<script type = "text/javaScript"> 

// JavaScript program to illustrate nested-if statement 

var i = 10; 

if (i == 10) { 

// First if statement 
if (i < 15) 
	document.write("i is smaller than 15"); 

// Nested - if statement 
// Will only be executed if statement above 
// it is true 
if (i < 12) 
	document.write("i is smaller than 12 too"); 
else
	document.write("i is greater than 15"); 
} 
< /script> 

Output:

i is smaller than 15
i is smaller than 12 too
  • if-else-if ladder Here, a user can decide among multiple options.The if statements are executed from the top down. As soon as one of the conditions controlling the if is true, the statement associated with that if is executed, and the rest of the ladder is bypassed. If none of the conditions is true, then the final else statement will be executed.
if (condition)
    statement;
else if (condition)
    statement;
.
.
else
    statement;


Example:

<script type = "text/javaScript"> 
// JavaScript program to illustrate nested-if statement 

var i = 20; 

if (i == 10) 
document.wrte("i is 10"); 
else if (i == 15) 
document.wrte("i is 15"); 
else if (i == 20) 
document.wrte("i is 20"); 
else
document.wrte("i is not present"); 
< /script> 

Output:

i is 20

How to Retrieve full Profile of LinkedIn User using Javascript

How to Retrieve full Profile of LinkedIn User using Javascript

I am trying to retrieve the full profile (especially job history and educational qualifications) of a linkedin user via the Javascript (Fetch LinkedIn Data Using JavaScript)

Here we are fetching LinkedIn data like Username, Email and other fields using JavaScript SDK.

Here we have 2 workarounds.

  1. Configuration of linkedIn developer api
  2. Javascript Code to fetch records

Configuration of linkedIn developer api

In order to fetch records, first we need to create developer api in linkedin which will act as token/identity while fetching data from other linkedin accounts.

So to create api, navigate to https://linkedin.com/developer/apps and click on 'Create Application'.

After navigating, fill in details like name, description and other required fields and then submit.

As we submit, it will create Client ID and Client Secret shown below, which we will be using in our code while communicating to fetch records from other LinkedIn account.

Note: We need to provide localhost Url here under Oauth 2.0. I am using my localhost, but you can probably use other production URLs under Oauth 2.0 where your app is configured. It will make your api  consider the Url as trusted which fetching records.

Javascript Code to fetch records

For getting user details like first name, last name,User image can be written as,

<script type="text/javascript" src="https://platform.linkedin.com/in.js">  
    api_key: XXXXXXX //Client ID  
    onLoad: OnLinkedInFrameworkLoad //Method that will be called on page load  
    authorize: true  
</script>  
<script type="text/javascript">  
    function OnLinkedInFrameworkLoad() {  
        IN.Event.on(IN, "auth", OnLinkedInAuth);  
    }  
  
    function OnLinkedInAuth() {  
        IN.API.Profile("me").result(ShowProfileData);  
    }  
  
    function ShowProfileData(profiles) {  
        var member = profiles.values[0];  
        var id = member.id;  
        var firstName = member.firstName;  
        var lastName = member.lastName;  
        var photo = member.pictureUrl;  
        var headline = member.headline;  
        //use information captured above  
        var stringToBind = "<p>First Name: " + firstName + " <p/><p> Last Name: " + lastName + "<p/><p>User ID: " + id + " and Head Line Provided: " + headline + "<p/>"  
        document.getElementById('profiles').innerHTML = stringToBind;  
    }  
</script>    

Kindly note we need to include 'https://platform.linkedin.com/in.js' as src under script type as it will act on this Javascript SDK provided by Linkedin.

In the same way we can also fetch records of any organization with the companyid as keyword.

<head>  
    <script type="text/javascript" src="https://platform.linkedin.com/in.js">  
        api_key: XXXXXXX ////Client ID  
        onLoad: onLinkedInLoad  
        authorize: true  
    </script>  
</head>  
  
<body>  
    <div id="displayUpdates"></div>  
    <script type="text/javascript">  
        function onLinkedInLoad() {  
            IN.Event.on(IN, "auth", onLinkedInAuth);  
            console.log("On auth");  
        }  
  
        function onLinkedInAuth() {  
            var cpnyID = XXXXX; //the Company ID for which we want updates  
            IN.API.Raw("/companies/" + cpnyID + "/updates?event-type=status-update&start=0&count=10&format=json").result(displayCompanyUpdates);  
            console.log("After auth");  
        }  
  
        function displayCompanyUpdates(result) {  
            var div = document.getElementById("displayUpdates");  
            var el = "<ul>";  
            var resValues = result.values;  
            for (var i in resValues) {  
                var share = resValues[i].updateContent.companyStatusUpdate.share;  
                var isContent = share.content;  
                var isTitled = isContent,  
                    isLinked = isContent,  
                    isDescription = isContent,  
                    isThumbnail = isContent,  
                    isComment = isContent;  
                if (isTitled) {  
                    var title = isContent.title;  
                } else {  
                    var title = "News headline";  
                }  
                var comment = share.comment;  
                if (isLinked) {  
                    var link = isContent.shortenedUrl;  
                } else {  
                    var link = "#";  
                }  
                if (isDescription) {  
                    var description = isContent.description;  
                } else {  
                    var description = "No description";  
                }  
                /* 
                if (isThumbnailz) { 
                var thumbnailUrl = isContent.thumbnailUrl; 
                } else { 
                var thumbnailUrl = "http://placehold.it/60x60"; 
                } 
                */  
                if (share) {  
                    var content = "<a target='_blank' href=" + link + ">" + comment + "</a><br>";  
                    //el += "<li><img src='" + thumbnailUrl + "' alt=''>" + content + "</li>";  
                    el += "<li><div>" + content + "</div></li>";  
                }  
                console.log(share);  
            }  
            el += "</ul>";  
            document.getElementById("displayUpdates").innerHTML = el;  
        }  
    </script>  
</body>  

We can get multiple metadata while fetching records for any any organization. We can get company updates as shown below.

Conclusion

We can also fetch any company specific data like company job updates/post, total likes, comments, and number of views along with a lot of metadata we can fetch which I have shown below.

Thank you for reading !

7 Best Javascript Iframe Libraries

7 Best Javascript Iframe Libraries

Iframes let you build user experiences into embeddable ‘cross-domain components’, which let users interact with other sites without being redirected. I have compiled 7 best Javascript iframe libraries.

Iframes let you build user experiences into embeddable ‘cross-domain components’, which let users interact with other sites without being redirected. I have compiled 7 best Javascript iframe libraries.

1. Zoid

A cross-domain component toolkit, supporting:

  • Render an iframe or popup on a different domain, and pass down props, including objects and functions
  • Call callbacks natively from the child window without worrying about post-messaging or cross-domain restrictions
  • Create and expose components to share functionality from your site to others!
  • Render your component directly as a React, Vue or Angular component!
    It's 'data-down, actions up' style components, but 100% cross-domain using iframes and popups!

Download


2. Postmate

Postmate is a promise-based API built on postMessage. It allows a parent page to speak with a child iFrame across origins with minimal effort.

Download


3. Iframe Resizer

Keep same and cross domain iFrames sized to their content with support for window/content resizing, in page links, nesting and multiple iFrames

Demo

Download


4. Iframely

Embed proxy. Supports over 1800 domains via custom parsers, oEmbed, Twitter Cards and Open Graph

Demo

Download


5. React Frame component

This component allows you to encapsulate your entire React application or per component in an iFrame.

Demo

Download


6. Seamless.js

A seamless iframe makes it so that visitors are unable to distinguish between content within the iframe and content beside the iframe. Seamless.js is a JavaScript library (with no dependencies) that makes working with iframes easy by doing all the seamless stuff for you automatically.

Demo

Download


7. Porthole

A proxy to safely communicate to cross-domain iframes in javascript

Demo

Download


Thank for read!