5 Javascript (ES6+) features that you should be using in 2019

5 Javascript (ES6+) features that you should be using in 2019

5 Javascript (ES6+) features that you should be using in 2019

We as developers must be trying to use the best tools and features in our disposition to make our job more easy and efficient.

Here I’m going to explain 5 features of modern Javascript that are very helpful and you are going to be using all the time:

  1. Let and const keywords
  2. Arrow functions
  3. Destructuring
  4. Spread operator
  5. Template literals

It’s 2019 and every modern browser support all these features so there is no excuse!.

You can run all the example code in your browser Developer Tools

1. let and const keywords

In Javascript var was the only way to declare a variable, the problem with var is it has no scope and you can declare the same variable multiple times, that is why now we have let and const keywords.

let

let allows you to declare variables that are limited in scope to the block, statement, or expression on which it is used. This is unlike the var keyword, which defines a variable globally, or locally to an entire function regardless of block scope.[1]

Let’s see an example:

var date = new Date("2015-01-01");
var region = "US";

// Some were further in the code
if (region === "US") {
  var date = new Date();
  console.log("New date", date); // We get the current date as expected
}

console.log(date); //Expecting 2015-01-01T00:00:00.000Z but we get the current date


We developers are bad at naming and if we are working with others the problem is magnified 10x. So is no rare that we use the same name for different things.

Let’s see how this work with let

let date = new Date("2015-01-01");
let region = "US";

// Some were further in the code
if (region === "US") {
  let date = new Date();
  console.log("New date", date); // We get the current date as expected
}

console.log(date); //We get 2015-01-01T00:00:00.000Z as expected :)


For me scoping is the more important feature of let. Other features are:

  1. Let and const keywords
  2. Arrow functions
  3. Destructuring
  4. Spread operator
  5. Template literals

const

const allows us to declare a constant variable, a value that shouldn’t change in our code. Let’s see an example:

const speedOfLight=299792458; //m*s-1

try {
  speedOfLight=300;
} catch(error) {
  console.log(error); // TypeError: Assignment to constant variable.
  // Note - error messages will vary depending on browser
}

console.log(speedOfLight); // Expected output 299792458


Other features of const:

  1. Let and const keywords
  2. Arrow functions
  3. Destructuring
  4. Spread operator
  5. Template literals

Note: Another good practice for variables is always declare variables on the top of your function or block scope, is more easy to keep track.

For this 2019 please please don’t use var anymore.

2. Arrow functions

Arrow functions (also known as fat arrow for the => symbol) has a shorter syntax that a regular function and allow us to write more concise code.

Let’s see the difference between old function expressions and arrow functions:

//ES5
let doubleNumbers = [1,2,3,4,5].map(function(number) { 
  return number*2;
});

//ES6 Arrow function
let doubleNumbers = [1,2,3,4,5].map((number) => { 
  return number*2 
});


In arrow functions, you don’t need parenthesis when you have only one argument and if a one-liner expression like this you can drop the return and the curly braces:

//ES6 Arrow function one-liner
let doubleNumbers = [1,2,3,4,5].map(number => number*2);

//ES6 Arrow function multiple arguments
handleClick((event, seconds) => {
  event.preventDefault();
  displayFireworks();
  showAnimation(seconds);
});


Arrow functions save us a lot of typing and also, in my opinion, make the code more readable.

What we lose with arrow functions is that we don’t have reference to this, arguments, super or new.target. This means that if you really need any of these arguments inside a function you should use traditional functions.

My recommendation is that you should use arrow functions as much as you can. In code, readability is key.

3. Destructuring

This is one of my favorite features of ES6.

Let’s see first an example:

// Old method
const myArray = ['apple', 'pear', 'orange', 'banana'];
let fruit1 = myArray[0];
let fruit2 = myArray[1];
let fruit3 = myArray[2];
let fruit4 = myArray[3];

//ES6 destructuring
let [fruit1, fruit2, fruit3, fruit4] = myArray; // much better isn't? 


We can use it on objects to:

let dog = {
 name: 'Toby',
 age: 3,
 breed: 'Beagle',
 features: {
   color: 'White and brown',
   favoriteToy: 'Plastic duck'
 }
}

// We can obtain the values like this with destructuring

let {name, age, breed} = dog;

// What if we want only name and age and all the other in another variable

let {name, age, ...info} = dog;


So what destructuring assignment allows us is extracting data from arrays or objects into distinct variables in an easy useful way.

I use it all the time for JSON objects.

Bonus

You can also go the other way around:

let firstName="Albert"
let lastName="Einstein"
let person = {firstName, lastName}

console.log(person.firstName); // "Albert"
console.log(person.lastName); // "Einstein"


4. Spread operator

Spread operator allows us to “spread” (duh!) or “explode” an array into its individual items.

Let’s see an example:

let first = [1,2,3];
let second = [4,5,6];

// If we do this
first.push(second);

// We get
console.log(first); // [1,2,3,[4,5,6]] that is not right

// Using the spread operator

first.push(...second);

console.log(first); // [1,2,3,4,5,6] that's what we wanted!


Using the spread operator (…) we manage to obtain each individual element without doing an iteration, this is very helpful in many situations. Let’s see another example:

let scores = [23, 45, 56];

function averageThreeScores(a, b, c) {
  let sum = a + b + c;
  return sum/3;
}

console.log(averageThreeScores(...scores)); // Result 41.333333...


Here we are using the spread operator to pass arguments to a function.

Spread operator also works with objects. As with arrays, the spread operator allows us to obtain each individual element of an object:

let name='Toby';
let age=3;
let features = {race: 'Beagle', size: 'small'};

let dog = {name, age, ...features}; // We expand the features object

console.log(dog); // {name: 'Toby', age: 3, race: 'Beagle', size: 'small'}


Spread operator also allow us to clone an object instead of using Object.assign:

let dog = {name: 'Toby', age: 3, race: 'Beagle', size: 'small'}

let puppy = {...dog, name: 'Max', age: 1}; // Clone dog object and modify its properties

console.log(puppy); // {name: 'Max', age: 1, race: 'Beagle', size: 'small'}
console.log(dog); // {name: 'Toby', age: 3, race: 'Beagle', size: 'small'}


As we can see we clone the dog object, and we changed the value of age and name without modifying the original object.

5. Template literals

We use strings everywhere, and we usually have to pass some variable to the string. Here is where Template literals come to the rescue.

Template literals are enclosed by the back-tick () character instead of double or single quotes.

Template literals can contain placeholders. These are indicated by the dollar sign and curly braces (${expression}):

let a = 5;
let b = 10;
console.log(`The sum of a and b is ${a+b} and the multiplication is ${a*b}`); 
// The sum of a and b is 15 and the multiplication is 50


We can also write multiline text like:

let name='Mike';
let age=30;
let country='Italy';

console.log(`${name} is
  ${age} years old and
  lives in ${country}
`);

// Mike is
//  30 years old and
//  lives in Italy


Here Javascript will show multiline text and will respect the spaces without the requirement of special characters such as \n.

References:

https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/

That is, for now, I hope that find this helpful. If you have any questions or anything that you want to add please leave a comment!

*Originally published by ****Olivers De Abreu ****at *dev.to

==============================

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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!