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Introduction to Web APIs in JavaScript

Earlier than we speak about APIs in JavaScript and find out how to use them, we have to know what precisely we imply by APIs. API stands for Software Programming Interface and is an idea that’s not restricted or particular to JavaScript, however is utilized in nearly all internet utility languages. Being an internet developer, it’s anticipated that you recognize about API, so let’s attempt to perceive the idea first. 

As an idea, API has been there since greater than 50 years, however in recent times it has turn into extremely popular and has outlined a distinct technique for the way we create our purposes. Now think about you’re creating an internet utility the place customers can enroll and speak about their latest travels, write tales, submit footage and share them. As an add-on they need to have the ability to share the identical throughout a number of platforms like Fb, Instagram and many others. How can we try this? We don’t have entry to the Instagram utility or their knowledge. We don’t know the way they’re managing their knowledge and whether or not knowledge from our utility will match into their databases.  

Let’s attempt to think about how Instagram would permit add-on with out APIs. Maybe we would drop an electronic mail to Instagram asking them to permit us entry to their databases the place we will write content material. They could have obtained tens of millions of different such requests from individuals who additionally want to make use of Instagram add-ons. Instagram will undergo our requests and the million others and possibly would use a fortunate draw to resolve who will get entry to their databases. That is clearly not an inexpensive resolution and with none cheap resolution all purposes on this planet will simply turn into remoted; which implies they’ll’t talk and may’t assist one another’s options. Fortunately our creativeness is simply that!

Thankfully, we live in a world with APIs round us which permit us to simply talk with different apps. I can create an utility the place I can use Google’s search, Fb’s feed, Instagram’s submit, twitter’s tweets multi functional app. That is all potential utilizing API. Because the identify suggests, it permits us to open an interface which might then be utilized by different apps to speak utilizing the interface. 

How does an API work?

The aim of API is to speak between apps with one another as middleman, the place each apps may need been constructed with totally different instruments and applied sciences. It may be achieved through the use of api requirements like REST, SOAP which define protocols or units of guidelines which the consumer (who must name) and server (who serves consumer’s requests) must observe. These requirements are key to communication. These requirements define what a request ought to appear to be and the format during which consumer ought to count on response from server. 

Each api exposes its endpoints (additionally referred to as entrypoints), which permits its consumer to make use of it to entry options of apis. For instance, in JavaScript, to work with DOM, it exposes Doc as an entrypoint to be able to work with a number of strategies. It permits its consumer to make use of it to be able to manipulate DOM. In JavaScript nonetheless we use containers, that are nothing however HTML controls which might name APIs and response will be rendered inside that management. 

JavaScript: An Introduction 

JavaScript is without doubt one of the most generally used programming languages, despite the fact that it’s primarily used on browsers to render HTML and CSS. It may additionally run on our servers to deal with consumer requests, join with databases and do nearly all the pieces some other programming language does on the server. This makes it a big instrument that must be discovered. 

Right here, we’re going to talk about about APIs that are supplied by JavaScript to work with nearly each facet of an internet utility. 

APIs in JavaScript 

JavaScript, being a really extensively used programming language has a really massive set of APIs accessible, which make a JavaScript developer’s life lots simpler. JavaScript can also be a multi-purpose language which implies it can’t solely work on browsers, but in addition on servers or telephones. To assist totally different platforms, it has a distinct set of APIs to work with. It additionally offers a wealthy set of controls and different options like storage on consumer that are all simply availed by JavaScript.  

Browser APIs in JavaScript 

Browsers use JavaScript to show internet pages, deal with consumer interactions, ship requests to servers and to obtain responses. To make all this potential, JavaScript offers browser APIs which can be utilized to carry out browser associated capabilities:  

  1. Working with DOM  

DOM stands for Doc Object Mannequin, which is a construction that holds all HTML controls on an internet web page. It not solely holds but in addition permits us so as to add take away controls from it. You may need labored with doc API which is used to get, push and even take away components from DOM, all of that is coming from JavaScript DOM API. 

Instance: doc.getElementById(“header”).textual content(“This can be a header”); 

  1. Request knowledge from server 

JavaScript is extensively used to optimize internet pages by updating solely part of a webpage as an alternative of loading the whole web page. for instance, while you like a submit on Fb, it doesn’t load the whole web page once more, it solely updates that explicit submit. Equally, after we tweet on Twitter it doesn’t reload the whole web page to point out new tweets. That is how JavaScript makes partial calls to the server utilizing fashionable fetch, AJAX apis. 


const response= await fetch(url); 
// when response is success which is standing 200 
if (response.okay)  else 
  1. Retailer knowledge at consumer 

Though now we have our databases working easily on servers processing terabytes of knowledge on daily basis, you may nonetheless wish to retailer a piece of knowledge on the consumer’s browsers to optimize the appliance performances. How can we try this? 

Once more JavaScript will present us the best way, by offering APIs like localStorage, sessionStorage which we will use to retailer knowledge on consumer’s browser and take away it every time we would like. The distinction between localStorage and sessionStorgae is that knowledge which we retailer in localStorage persists even after closing the browser or tab,  whereas knowledge saved in sessionStorage will get cleared as quickly because the tab or browser is closed. Now each of those have its personal benefits relying in your requirement.

sessionStorage.setItem('key', worth); 
localStorage.setItem('key', worth); 
  1. Work with Graphics 

There are lot of fashionable purposes the place you may need seen  2D or 3D graphics created utilizing consumer’s interplay permitting customers to create such drawings, and I’m not speaking about simply CSS (Cascaded Type Sheets). Sure, CSS has its function to play, however to permit customers to create 2D/3D drawings on the internet we want extra than simply CSS. JavaScript offers canvas api which can be utilized to work with pixels on internet web page to attract 2D/ 3D photographs which might be inside <canvas> html tag.

Third Social gathering APIs.  

Integration with different purposes, the buildings of which we don’t have a lot details about, will be tough. However JavaScript permits us to combine with many fashionable third-party apps like Twitter, YouTube, Fb. 

For instance, you might have your organization’s web site the place you additionally wish to show latest tweets that your organization’s Twitter account has tweeted. How can we try this? JavaScript’s Twitter API is the reply. This isn’t just for Twitter, however a lot of different fashionable apps will be built-in into your personal internet web page utilizing JavaScript’s third occasion APIs. 

Net Audio API  

Audio API in JavaScript offers a clean implementation of audio controls over a webpage. This contains a number of play controls on audio, and audio results on the internet. Net Audio API has a number of interfaces which embody operations associated to visualization results, audio locations, merging audio channels and audio processing. 


  <audio src=""></audio> 
  <enter kind="vary" min="zero" max="1" step="zero.01" worth="1"> 

Geolocation API

There are lots of internet apps which work finest with data of consumer’s areas, for instance, if you’re searching for eating places close by, you’ll get higher outcomes if Google is aware of your location. It is clearly as much as the consumer’s consent in the event that they wish to share their location or not as a result of privateness issues, but when they do wish to share, geolocation API offers location of customers to internet purposes. 


var tackle = doc.getElementById("tackle"); 
perform accessUserLocation()  
perform displayLocation(location) 

Historical past API  

Historical past API is one other helpful though hardly ever used API, used for those who wish to permit consumer to traverse forwards and backwards on an internet utility. Historical past API runs with window objects utilizing three totally different strategies available– go, again and ahead. 


// Go to web page visited beforehand 
window.historical past.again(); 
// Traverse to ahead on internet web page. 
window.historical past.ahead(); 
// Transfer ahead by 1 web page 
window.historical past.go(1); 

Net Staff API  

Staff will be created utilizing constructors in JavaScript, which might run a JavaScript file below employee thread context, which is totally different from the context of home windows in JavaScript. There are a couple of exceptions on what sort of code we will run below employee thread, for instance we will’t manipulate DOM utilizing employee thread. With this a query arises– if employee thread is totally different kind predominant window thread, then how do they impart? As a result of despite the fact that it’s working in a distinct thread, the employee can nonetheless execute many window strategies. To make this potential, the employee and predominant thread talk utilizing postMessage() technique; to ship knowledge every time onmessage occasion is known as and dealt with. 


const employee = new Employee('enter.js'); 

Right here enter file which is a JavaScript file will comprise the code which you want the employee thread to execute. 

Most Common JavaScript APIs 

  • Browser APIs  We’ve mentioned them intimately and since JavaScript leads how internet purposes are rendered on browser, the recognition of browser APIs is clear. 
  • Canvas APIs  That is one other favourite API of many builders who work within the graphics area and wish interactive purposes for his or her consumer to simply work with drawings and graphics on internet pages. 
  • SocialMedia APIs – This is quite common these days. Any internet utility that targets an viewers, wants social media integrations of their app, akin to Fb, Twitter, Instagram APIs, the place they’ll showcase latest actions on their internet web page. 
  • Storage APIs  Each website I browse now a days pops up a panel asking me to simply accept cookies settings. Why? As a result of it helps the purposes work nicely with consumer’s interplay and responses to the app, and the storage is just not restricted to cookies. sessionStorage and localStorage are extensively utilized in JavaScript purposes to retailer consumer’s data on consumer’s browsers. We simply can’t think about a life with out storage APIs in JavaScript! 

JavaScript instruments and relationship between them

JavaScript Libraries

 There are JavaScript libraries like jQuery and React which implement JavaScript with their very own new syntax. For instance, the best way we entry our DOM utilizing vanilla JavaScript and the best way jQuery does it’s totally different, however in the long run, each use the identical API which now we have mentioned above. One other instance is when utilizing React, the place it extends JavaScript with JSX to embed JavaScript with HTML in React parts.

JavaScript Frameworks

JavaScript Frameworks like Angular and Vue make many of the JavaScript APIs as they’re constructed on high of JavaScript. The distinction between the frameworks is within the construction, knowledge circulation and totally different patterns which they use to make it simpler to work with JavaScript and implement its APIs.  

For instance, Angular makes use of Dependency Injection to inject providers into the element’s constructors, making it a subtle type of implementing inversion management which might be not this clean with vanilla JavaScript. Frameworks like Angular attempt to forestall customers from manipulating DOM straight as it’s an costly operation. Nonetheless, it doesn’t imply it doesn’t replace DOM in any respect. In the tip, Angular makes use of DOM manipulation internally in fairly an efficient means, utilizing the similar APIs now we have mentioned above.


An API will be in comparison with a cellphone with limitless speak time that’s given to an utility, permitting it to speak with all different purposes on this planet. Why do we want this? As a result of one utility doesn’t must and may’t do all the pieces. They want one another’s assist. 

APIs will be for exterior as nicely inner use. Exterior APIs permits an app to speak with different apps, and inner or built-in APIs permit builders to work successfully with the instruments. JavaScript being the preferred language on this planet is conscious of this and therefore presents loads of interfaces for us as builders to make use of in our purposes. Be it working with storage, creating controls, integrating with Twitter, presenting media, or drawing graphics, JavaScript won’t allow you to down.  

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