The 3 Important Strategies to Improve Your Search Engine Rankings

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We’ve learned to live with desktop page speed as a Google ranking factor, and now we’ve accepted that mobile page speed is a ranking factor, too. After the search giant announced that they were going to roll out the Speed Update, they changed their approach to measuring page speed via the Google PageSpeed Insights tool, as well.My team wanted to know if there was any correlation between a page’s speed and a page’s positions in mobile search results, so we ran experiments to find out. We conducted one before and one immediately after the Speed Update. The results? Surprising.

Based on what we learned, these are top three ways you can use page speed as an opportunity to improve your ranking.

1: User Engagement

Simply, user engagement is the measurement of how well your website engages Internet users. A focus on optimizing your website to improve the SEO factors above related to user engagement is the key to this strategy.

SEO ranking factors for user engagement include the following:

Direct website visits – users who visit your website by directly typing in your URL address into their Internet browser (in other websites, the popularity of your website is one of the signals) Time on site – the amount of time users spend on your website Pages per session – the average number of pages users view during a visit to your website Bounce rate – the percentage measure of website visitors who leave your site after viewing only one page without interacting with it 3 Quick Ways to Improve User Engagement Create content that helps users satisfy the problem they are having or challenge they are trying to solve as expressed by the query they use during a search Link to deeper, more specific content within your website giving the user a path to progress and become more immersed in your content and your expertise Create content in multiple forms such as lists, photos that aid the message, videos, and recommended steps or actions Your website design should be appealing to your target market, showcase your brand, and create an environment that makes your content highly and easily readable— particularly on a mobile device.

Quickly provide information on how your products/ services work and an incentive motivating users to perform a certain action; whether that’s calling you, filling out a contact form, making a purchase, etc. Check For Digital Marketing Companies in Vivid Digital

2: Link Structure

Link building, content marketing, link solicitation— it has many names. The most overlooked and undervalued tactic in all of search engine optimization, link structure is how your website interconnects with itself and other websites across the Internet.

Essentially, link structure involves how your website links to other pages within itself (internal links), how your website links to other websites (outbound links), and how other websites link to yours (backlinks/ inbound links).

A focus on optimizing your website to improve the SEO factors involving link structure is the key to this strategy. The SEO ranking factors involving linking include:

Total referring domains – the total number of domains that link to your website Total backlinks – the total number of times (or links) other websites link to your website Total referring IPs – the total number of IP addresses involved in the backlinks to your website Total follow backlinks – the total amount of backlinks counting towards your website’s PageRank (See the difference between follow vs. no follow links) 3 Quick Ways to Improve Your Link Structure Avoid overloading links to your internal top level pages Create a white hat SEO link solicitation plan to get more high-quality backlinks Use appropriately descriptive anchor text for all your links (No more links with clickable text saying, “Click here.”) Your links should briefly describe the type of content the link goes to, the page’s benefit, OR the action the user should take when they land on that page.

3. Increase your Optimization Score.

The findings of our experiment are curious: while we found no correlation between a mobile site’s position and site’s FCP/DCL metrics, we did find an extremely high correlation (0.97!) between a mobile site’s position in search results and its average Optimization Score.

While there is little we can do to influence FCP/DCL metrics (as they are based not only on the actual speed of your site, but also on the users’ connection speeds and their devices), improving your Optimization Score is crucial. The good news? It’s also totally manageable. For SEO Services in Hyderabad visit  here

Google provides a list of recommendations on how to deal with the factors that can lower your Optimization Score in PageSpeed Insights.

Here is a quick list of what you can do:

Avoid landing page redirects. They slow down rendering of a page, which negatively affects desktop and mobile experience. Enable compression. Small image size cuts time spent to download the resource as well as data usage for the client, plus it improves pages’ rendering time. Improve server response time. 53% of mobile users will leave a page if it does not load in less than 3 seconds. Implement a caching policy. Its absence leads to a great number of roundtrips between the client and server during the resources’ fetching process, which leads to delays, page rendering blocking, and higher costs for visitors. Minify resources (HTML, CSS, and JavaScript). It helps to cut on redundant data from the resources delivered to visitors. Optimize images. They account for about 60% of a page size, and heavy images can significantly slow down site’s rendering. Optimize CSS delivery. A page needs to process CSS prior to its rendering. When CSS is full of render-blocking external stylesheets, the process requires a great number of roundtrips that delay rendering. Prioritize visible content. If above-the-fold content exceeds 14,6kB compressed, it requires multiple roundtrips between the server and user’s browser to load and render content. Remove render-blocking JavaScript. Every time a browser encounters it in site’s HTML, it has to stop and execute this script, which slows down the rendering process. If you’re unsure how to implement any of the above page speed optimizations, talk to your website developer or check out more tips here.

 

Top 4 Digital Marketing Strategies You Need to Know for 2019

Digital marketing is ever-changing as innovation creates new opportunities for marketers every day. Along with it, your strategy must change and grow with technology to keep ahead of your competitors. Trending digital marketing strategies keep marketers on their toes trying to innovate new and different ways to engage their audiences.

In this blog, we’ll take stock of the digital marketing landscape in 2018, discuss what’s changed and what’s new, and see where you should be investing your energy for 2019.

1. Virtual and Augmented Reality

Smart companies are leveraging mobile cameras to improve their customer experience. Through VR and AR, you can improve brand engagement and help with pre-purchase decisions by bringing your products to life. By allowing customers to engage in more profound ways through immersive experiences, they are better equipped to find what they are looking for and be delighted in doing so.

Consider Amazon, who set up Oculus Rift VR booths around Prime Day, allowing shoppers to experience a wide range of products from nerf guns to refrigerators as they would in physical reality. By empowering potential buyers to literally picture themselves owning products and simulate this potential reality, VR preemptively addresses needs and pain points, greatly enhancing the customer journey.

When getting users to a specific physical location isn’t possible, augmented reality can provide greater flexibility and reach through integration with mobile apps. StubHub executed this masterfully, introducing an AR feature that allowed fans to better understand the city and stadium ahead of this year’s Super Bowl. Potential ticket buyers could click to see a 3D map of the stadium, parking, transit lines, and more, making it easier to envision themselves at the event.

By deploying virtual or augmented reality strategically, you have a unique opportunity to supply consumers with the depth of pre-purchase information they crave, while minimizing the effort they must take to obtain it. For Digital Marketing Company visit Vivid Digital  

2. Artificial Intelligence

In the past, digital marketers have been hesitant to incorporate artificial intelligence into their strategies. But as AI continues to prove itself useful for simplifying data-based experiences and improving user experience, confidence in it has increased.

KLM has done a great job with this, creating a plug-in with Messenger that streamlines everything from booking to check-in and flight status updates. It’s a win-win for both sides: travelers can access all their travel info from anywhere, and KLM can supply it to them without tying up personnel.

Chatbots can also be valuable for facilitating pre-purchase decisions. For instance, Bing’s Business Bot, which is embedded into search results, allows interested users to have basic questions answered by the businesses around them. If their query is not on the pre-configured list, the bot refers them to a phone number. The bot also asks business owners additional questions based on what users are looking for, so that common requests can be answered faster in the future. By refining responses to fit user needs, artificial intelligence allows you to help users better and faster over time.

3. Visual and Voice Search

Search is evolving beyond its text-only origins, meaning that visual and voice search deserve serious consideration now. Think of visual search as a sort of reverse search, using images to find text-based info instead of the other way around. Google, Microsoft, and Pinterest have all jumped into the fray, and it’s only going to get bigger over time. Marketers can gain an edge here by preparing tailor-made content to await potential customers after their image searches, while also gaining even more insights into their preferences.

Dominos Voice Search Example

Voice search also continues to grow as a way for consumers to find more information without even having to lift a finger. Domino’s has done well here, teaming up with Amazon Echo to let customers order pizza hands-free. Allowing people to interact with you via voice search makes their life easier, and offers a chance to incorporate brand personality and tone in the way you respond. The dynamics of voice search also present a challenge for digital marketers, who must figure out how to optimize for both humans and devices.  SEO Agency in Hyderabad visit Vivid Digital

4. Vertical Video

With the shift from desktop to mobile a consistent digital marketing consideration, it should come as no surprise that mobile video ads continue to be hot. Savvy marketers are using videos to both engage their audiences in-app between tasks and on social platforms.

What’s new, however, is the movement towards more vertical video. Instagram’s recent introduction of IGTV continues this trend, allowing users to create long-form vertical videos. While advertising is not available (yet) on IGTV, its great place for brands to share their longer content organically. The success of IGTV and other similar platforms is worth keeping an eye on, as it could cause a major shift in favor of vertical video. If this is the case, marketers will need to create horizontal and vertical assets to reach their audience fully.

Staying Ahead of the Competition

These emerging digital marketing strategies make it easier to both reach customers when and where they are ready to buy and improve their experience post-purchase. Competitive companies know that capitalizing on new forms of content and technology will help them capture new audiences on fresh playing fields.

So which of these hot new digital marketing strategies do you plan on implementing? Let me know in the comments below!

Node.js Child Processes: Everything you need to know

Single-threaded, non-blocking performance in Node.js works great for a single process. But eventually, one process in one CPU is not going to be enough to handle the increasing workload of your application.

No matter how powerful your server may be, a single thread can only support a limited load.

The fact that Node.js runs in a single thread does not mean that we can’t take advantage of multiple processes and, of course, multiple machines as well.

Using multiple processes is the best way to scale a Node application. Node.js is designed for building distributed applications with many nodes. This is why it’s named Node. Scalability is baked into the platform and it’s not something you start thinking about later in the lifetime of an application.

This article is a write-up of part of my Pluralsight course about Node.js. I cover similar content in video format there.

Please note that you’ll need a good understanding of Node.js events and streams before you read this article. If you haven’t already, I recommend that you read these two other articles before you read this one:

The Child Processes Module

We can easily spin a child process using Node’s child_process module and those child processes can easily communicate with each other with a messaging system.

The child_process module enables us to access Operating System functionalities by running any system command inside a, well, child process.

We can control that child process input stream, and listen to its output stream. We can also control the arguments to be passed to the underlying OS command, and we can do whatever we want with that command’s output. We can, for example, pipe the output of one command as the input to another (just like we do in Linux) as all inputs and outputs of these commands can be presented to us using Node.js streams.

Note that examples I’ll be using in this article are all Linux-based. On Windows, you need to switch the commands I use with their Windows alternatives.

There are four different ways to create a child process in Node: spawn()fork()exec(), and execFile().

We’re going to see the differences between these four functions and when to use each.

Spawned Child Processes

The spawn function launches a command in a new process and we can use it to pass that command any arguments. For example, here’s code to spawn a new process that will execute the pwd command.

const { spawn } = require('child_process');
const child = spawn('pwd');

We simply destructure the spawn function out of the child_process module and execute it with the OS command as the first argument.

The result of executing the spawn function (the child object above) is a ChildProcess instance, which implements the EventEmitter API. This means we can register handlers for events on this child object directly. For example, we can do something when the child process exits by registering a handler for the exit event:

child.on('exit', function (code, signal) {
  console.log('child process exited with ' +
              `code ${code} and signal ${signal}`);
});

The handler above gives us the exit code for the child process and the signal, if any, that was used to terminate the child process. This signalvariable is null when the child process exits normally.

The other events that we can register handlers for with the ChildProcessinstances are disconnecterrorclose, and message.

  • The disconnect event is emitted when the parent process manually calls the child.disconnect function.
  • The error event is emitted if the process could not be spawned or killed.
  • The close event is emitted when the stdio streams of a child process get closed.
  • The message event is the most important one. It’s emitted when the child process uses the process.send() function to send messages. This is how parent/child processes can communicate with each other. We’ll see an example of this below.

Every child process also gets the three standard stdio streams, which we can access using child.stdinchild.stdout, and child.stderr.

When those streams get closed, the child process that was using them will emit the close event. This close event is different than the exit event because multiple child processes might share the same stdio streams and so one child process exiting does not mean that the streams got closed.

Since all streams are event emitters, we can listen to different events on those stdio streams that are attached to every child process. Unlike in a normal process though, in a child process, the stdout/stderr streams are readable streams while the stdin stream is a writable one. This is basically the inverse of those types as found in a main process. The events we can use for those streams are the standard ones. Most importantly, on the readable streams, we can listen to the data event, which will have the output of the command or any error encountered while executing the command:

child.stdout.on('data', (data) => {
  console.log(`child stdout:\n${data}`);
});

child.stderr.on('data', (data) => {
  console.error(`child stderr:\n${data}`);
});

The two handlers above will log both cases to the main process stdout and stderr. When we execute the spawn function above, the output of the pwdcommand gets printed and the child process exits with code 0, which means no error occurred.

We can pass arguments to the command that’s executed by the spawnfunction using the second argument of the spawn function, which is an array of all the arguments to be passed to the command. For example, to execute the find command on the current directory with a -type f argument (to list files only), we can do:

const child = spawn('find', ['.', '-type', 'f']);

If an error occurs during the execution of the command, for example, if we give find an invalid destination above, the child.stderr data event handler will be triggered and the exit event handler will report an exit code of 1, which signifies that an error has occurred. The error values actually depend on the host OS and the type of error.

A child process stdin is a writable stream. We can use it to send a command some input. Just like any writable stream, the easiest way to consume it is using the pipe function. We simply pipe a readable stream into a writable stream. Since the main process stdin is a readable stream, we can pipe that into a child process stdin stream. For example:

const { spawn } = require('child_process');

const child = spawn('wc');

process.stdin.pipe(child.stdin)

child.stdout.on('data', (data) => {
  console.log(`child stdout:\n${data}`);
});

In the example above, the child process invokes the wc command, which counts lines, words, and characters in Linux. We then pipe the main process stdin (which is a readable stream) into the child process stdin (which is a writable stream). The result of this combination is that we get a standard input mode where we can type something and when we hit Ctrl+D, what we typed will be used as the input of the wc command.

We can also pipe the standard input/output of multiple processes on each other, just like we can do with Linux commands. For example, we can pipe the stdout of the find command to the stdin of the wc command to count all the files in the current directory: For Top web design company check Vivid Designs

const { spawn } = require('child_process');

const find = spawn('find', ['.', '-type', 'f']);
const wc = spawn('wc', ['-l']);

find.stdout.pipe(wc.stdin);

wc.stdout.on('data', (data) => {
  console.log(`Number of files ${data}`);
});

I added the -l argument to the wc command to make it count only the lines. When executed, the code above will output a count of all files in all directories under the current one.

Shell Syntax and the exec function

By default, the spawn function does not create a shell to execute the command we pass into it. This makes it slightly more efficient than the exec function, which does create a shell. The exec function has one other major difference. It buffers the command’s generated output and passes the whole output value to a callback function (instead of using streams, which is what spawn does).

Here’s the previous find | wc example implemented with an exec function.

const { exec } = require('child_process');

exec('find . -type f | wc -l', (err, stdout, stderr) => {
  if (err) {
    console.error(`exec error: ${err}`);
    return;
  }

  console.log(`Number of files ${stdout}`);
});

Since the exec function uses a shell to execute the command, we can use the shell syntax directly here making use of the shell pipe feature.

Note that using the shell syntax comes at a security risk if you’re executing any kind of dynamic input provided externally. A user can simply do a command injection attack using shell syntax characters like ; and $ (for example, command + ’; rm -rf ~’ )

The exec function buffers the output and passes it to the callback function (the second argument to exec) as the stdout argument there. This stdoutargument is the command’s output that we want to print out.

The exec function is a good choice if you need to use the shell syntax and if the size of the data expected from the command is small. (Remember, execwill buffer the whole data in memory before returning it.)

The spawn function is a much better choice when the size of the data expected from the command is large, because that data will be streamed with the standard IO objects.

We can make the spawned child process inherit the standard IO objects of its parents if we want to, but also, more importantly, we can make the spawnfunction use the shell syntax as well. Here’s the same find | wc command implemented with the spawn function:

const child = spawn('find . -type f | wc -l', {
  stdio: 'inherit',
  shell: true
});

Because of the stdio: 'inherit' option above, when we execute the code, the child process inherits the main process stdinstdout, and stderr. This causes the child process data events handlers to be triggered on the main process.stdout stream, making the script output the result right away.

Because of the shell: true option above, we were able to use the shell syntax in the passed command, just like we did with exec. But with this code, we still get the advantage of the streaming of data that the spawn function gives us. This is really the best of both worlds.

There are a few other good options we can use in the last argument to the child_process functions besides shell and stdio. We can, for example, use the cwd option to change the working directory of the script. For example, here’s the same count-all-files example done with a spawn function using a shell and with a working directory set to my Downloads folder. The cwdoption here will make the script count all files I have in ~/Downloads:

const child = spawn('find . -type f | wc -l', {
  stdio: 'inherit',
  shell: true,
  cwd: '/Users/samer/Downloads'
});

Another option we can use is the env option to specify the environment variables that will be visible to the new child process. The default for this option is process.env which gives any command access to the current process environment. If we want to override that behavior, we can simply pass an empty object as the env option or new values there to be considered as the only environment variables:

const child = spawn('echo $ANSWER', {
  stdio: 'inherit',
  shell: true,
  env: { ANSWER: 42 },
});

The echo command above does not have access to the parent process’s environment variables. It can’t, for example, access $HOME, but it can access $ANSWER because it was passed as a custom environment variable through the env option.

One last important child process option to explain here is the detachedoption, which makes the child process run independently of its parent process.

Assuming we have a file timer.js that keeps the event loop busy:

setTimeout(() => {  
  // keep the event loop busy
}, 20000);

We can execute it in the background using the detached option:

const { spawn } = require('child_process');

const child = spawn('node', ['timer.js'], {
  detached: true,
  stdio: 'ignore'
});

child.unref();

The exact behavior of detached child processes depends on the OS. On Windows, the detached child process will have its own console window while on Linux the detached child process will be made the leader of a new process group and session.

If the unref function is called on the detached process, the parent process can exit independently of the child. This can be useful if the child is executing a long-running process, but to keep it running in the background the child’s stdio configurations also have to be independent of the parent.

The example above will run a node script (timer.js) in the background by detaching and also ignoring its parent stdio file descriptors so that the parent can terminate while the child keeps running in the background.

The execFile function

If you need to execute a file without using a shell, the execFile function is what you need. It behaves exactly like the exec function, but does not use a shell, which makes it a bit more efficient. On Windows, some files cannot be executed on their own, like .bat or .cmd files. Those files cannot be executed with execFile and either exec or spawn with shell set to true is required to execute them.

The *Sync function

The functions spawnexec, and execFile from the child_process module also have synchronous blocking versions that will wait until the child process exits.

const { 
  spawnSync, 
  execSync, 
  execFileSync,
} = require('child_process');

Those synchronous versions are potentially useful when trying to simplify scripting tasks or any startup processing tasks, but they should be avoided otherwise.

The fork() function

The fork function is a variation of the spawn function for spawning node processes. The biggest difference between spawn and fork is that a communication channel is established to the child process when using fork, so we can use the send function on the forked process along with the global process object itself to exchange messages between the parent and forked processes. We do this through the EventEmitter module interface. Here’s an example: Web designing services in Hyderabad visit Vivid Designs 

The parent file, parent.js:

const { fork } = require('child_process');

const forked = fork('child.js');

forked.on('message', (msg) => {
  console.log('Message from child', msg);
});

forked.send({ hello: 'world' });

The child file, child.js:

process.on('message', (msg) => {
  console.log('Message from parent:', msg);
});

let counter = 0;

setInterval(() => {
  process.send({ counter: counter++ });
}, 1000);

In the parent file above, we fork child.js (which will execute the file with the node command) and then we listen for the message event. The messageevent will be emitted whenever the child uses process.send, which we’re doing every second.

To pass down messages from the parent to the child, we can execute the sendfunction on the forked object itself, and then, in the child script, we can listen to the message event on the global process object.

When executing the parent.js file above, it’ll first send down the { hello: 'world' } object to be printed by the forked child process and then the forked child process will send an incremented counter value every second to be printed by the parent process.

Let’s do a more practical example about the fork function.

Let’s say we have an http server that handles two endpoints. One of these endpoints (/compute below) is computationally expensive and will take a few seconds to complete. We can use a long for loop to simulate that:

const http = require('http');
const longComputation = () => {
  let sum = 0;
  for (let i = 0; i < 1e9; i++) {
    sum += i;
  };
  return sum;
};
const server = http.createServer();
server.on('request', (req, res) => {
  if (req.url === '/compute') {
    const sum = longComputation();
    return res.end(`Sum is ${sum}`);
  } else {
    res.end('Ok')
  }
});

server.listen(3000);

This program has a big problem; when the the /compute endpoint is requested, the server will not be able to handle any other requests because the event loop is busy with the long for loop operation.

There are a few ways with which we can solve this problem depending on the nature of the long operation but one solution that works for all operations is to just move the computational operation into another process using fork.

We first move the whole longComputation function into its own file and make it invoke that function when instructed via a message from the main process:

In a new compute.js file:

const longComputation = () => {
  let sum = 0;
  for (let i = 0; i < 1e9; i++) {
    sum += i;
  };
  return sum;
};

process.on('message', (msg) => {
  const sum = longComputation();
  process.send(sum);
});

Now, instead of doing the long operation in the main process event loop, we can fork the compute.js file and use the messages interface to communicate messages between the server and the forked process.

const http = require('http');
const { fork } = require('child_process');

const server = http.createServer();

server.on('request', (req, res) => {
  if (req.url === '/compute') {
    const compute = fork('compute.js');
    compute.send('start');
    compute.on('message', sum => {
      res.end(`Sum is ${sum}`);
    });
  } else {
    res.end('Ok')
  }
});

server.listen(3000);

When a request to /compute happens now with the above code, we simply send a message to the forked process to start executing the long operation. The main process’s event loop will not be blocked.

Once the forked process is done with that long operation, it can send its result back to the parent process using process.send.

In the parent process, we listen to the message event on the forked child process itself. When we get that event, we’ll have a sum value ready for us to send to the requesting user over http.

The code above is, of course, limited by the number of processes we can fork, but when we execute it and request the long computation endpoint over http, the main server is not blocked at all and can take further requests.

Node’s cluster module, which is the topic of my next article, is based on this idea of child process forking and load balancing the requests among the many forks that we can create on any system.

That’s all I have for this topic. Thanks for reading! Until next time!

Source

Functional setState is the future of React

Justice Mba

Update: I gave a follow up talk on this topic at React Rally. While this post is more about the “functional setState” pattern, the talk is more about understanding setState deeply

React has popularized functional programming in JavaScript. This has led to giant frameworks adopting the Component-based UI pattern that React uses. And now functional fever is spilling over into the web development ecosystem at large.

But the React team is far from relenting. They continue to dig deeper, discovering even more functional gems hidden in the legendary library.

So today I reveal to you a new functional gold buried in React, best kept React secret — Functional setState!

Okay, I just made up that name… and it’s not entirely new or a secret. No, not exactly. See, it’s a pattern built into React, that’s only known by few developers who’ve really dug in deep. And it never had a name. But now it does — Functional setState!

Going by Dan Abramov’s words in describing this pattern, Functional setState is a pattern where you

“Declare state changes separately from the component classes.”

Huh?

Okay… what you already know

React is a component based UI library. A component is basically a function that accept some properties and return a UI element.

function User(props) {
  return (
    <div>A pretty user</div>
  );
}

A component might need to have and manage its state. In that case, you usually write the component as a class. Then you have its state live in the class constructor function:

class User {
  constructor () {
    this.state = {
      score : 0
    };
  }
  render () {
    return (
      <div>This user scored {this.state.score}</div>
    );
  }
}

To manage the state, React provides a special method called setState(). You use it like this:

class User {
  ...
  increaseScore () {
    this.setState({score : this.state.score + 1});
  }
  ...
}

Note how setState() works. You pass it an object containing part(s) of the state you want to update. In other words, the object you pass would have keys corresponding to the keys in the component state, then setState() updates or sets the state by merging the object to the state. Thus, “set-State”.

What you probably didn’t know

Remember how we said setState() works? Well, what if I told you that instead of passing an object, you could pass a function?

Yes. setState() also accepts a function. The function accepts the previousstate and current props of the component which it uses to calculate and return the next state. See it below:

this.setState(function (state, props) {
 return {
  score: state.score - 1
 }
});

Note that setState() is a function, and we are passing another function to it(functional programming… functional setState) . At first glance, this might seem ugly, too many steps just to set-state. Why will you ever want to do this?

Why pass a function to setState?

The thing is, state updates may be asynchronous.

Think about what happens when setState() is called. React will first merge the object you passed to setState() into the current state. Then it will start that reconciliation thing. It will create a new React Element tree (an object representation of your UI), diff the new tree against the old tree, figure out what has changed based on the object you passed to setState() , then finally update the DOM.

Whew! So much work! In fact, this is even an overly simplified summary. But trust in React!

React does not simply “set-state”.

Because of the amount of work involved, calling setState() might not immediately update your state.

React may batch multiple setState() calls into a single update for performance.

What does React mean by this?

First, “multiple setState() calls” could mean calling setState() inside a single function more than once, like this:

...
state = {score : 0};
// multiple setState() calls increaseScoreBy3 () { this.setState({score : this.state.score + 1}); this.setState({score : this.state.score + 1}); this.setState({score : this.state.score + 1}); }
...

Now when React, encounters “multiple setState() calls”, instead of doing that “set-state” three whole times, React will avoid that huge amount of work I described above and smartly say to itself: “No! I’m not going to climb this mountain three times, carrying and updating some slice of state on every single trip. No, I’d rather get a container, pack all these slices together, and do this update just once.” And that, my friends, is batching!

Remember that what you pass to setState() is a plain object. Now, assume anytime React encounters “multiple setState() calls”, it does the batching thing by extracting all the objects passed to each setState() call, merges them together to form a single object, then uses that single object to do setState() . For Website design services check Vivid Designs

In JavaScript merging objects might look something like this:

const singleObject = Object.assign(
  {}, 
  objectFromSetState1, 
  objectFromSetState2, 
  objectFromSetState3
);

This pattern is known as object composition.

In JavaScript, the way “merging” or composing objects works is: if the three objects have the same keys, the value of the key of the last object passed to Object.assign() wins. For example:

const me  = {name : "Justice"}, 
      you = {name : "Your name"},
      we  = Object.assign({}, me, you);
we.name === "Your name"; //true
console.log(we); // {name : "Your name"}

Because you are the last object merged into we, the value of name in the you object — “Your name” — overrides the value of name in the me object. So “Your name” makes it into the we object… you win! 🙂

Thus, if you call setState() with an object multiple times — passing an object each time — React will merge. Or in other words, it will compose a new object out of the multiple objects we passed it. And if any of the objects contains the same key, the value of the key of the last object with same key is stored. Right?

That means that, given our increaseScoreBy3 function above, the final result of the function will just be 1 instead of 3, because React did not immediatelyupdate the state in the order we called setState() . But first, React composed all the objects together, which results to this: {score : this.state.score + 1} , then only did “set-state” once — with the newly composed object. Something like this: User.setState({score : this.state.score + 1}.

To be super clear, passing object to setState() is not the problem here. The real problem is passing object to setState() when you want to calculate the next state from the previous state. So stop doing this. It’s not safe!

Because this.props and this.state may be updated asynchronously, you should not rely on their values for calculating the next state.

Here is a pen by Sophia Shoemaker that demos this problem. Play with it, and pay attention to both the bad and the good solutions in this pen:

Functional setState to the rescue

If you’ve not spent time playing with the pen above, I strongly recommend that you do, as it will help you grasp the core concept of this post.

While you were playing with the pen above, you no doubt saw that functional setState fixed our problem. But how, exactly?

Let’s consult the Oprah of React — Dan.

Note the answer he gave. When you do functional setState…

Updates will be queued and later executed in the order they were called.

So, when React encounters “multiple functional setState() calls” , instead of merging objects together, (of course there are no objects to merge) React queues the functions “in the order they were called.”

After that, React goes on updating the state by calling each functions in the “queue”, passing them the previous state — that is, the state as it was before the first functional setState() call (if it’s the first functional setState() currently executing) or the state with the latest update from the previous functional setState() call in the queue.

Again, I think seeing some code would be great. This time though, we’re gonna fake everything. Know that this is not the real thing, but is instead just here to give you an idea of what React is doing.

Also, to make it less verbose, we’ll use ES6. You can always write the ES5 version later if you want.

First, let’s create a component class. Then, inside it, we’ll create a fake setState() method. Also, our component would have a increaseScoreBy3()method, which will do a multiple functional setState. Finally, we’ll instantiate the class, just as React would do.

class User{
  state = {score : 0};
  //let's fake setState
  setState(state, callback) {
    this.state = Object.assign({}, this.state, state);
    if (callback) callback();
  }
  // multiple functional setState call
  increaseScoreBy3 () {
    this.setState( (state) => ({score : state.score + 1}) ),
    this.setState( (state) => ({score : state.score + 1}) ),
    this.setState( (state) => ({score : state.score + 1}) )
  }
}
const Justice = new User();

Note that setState also accepts an optional second parameter — a callback function. If it’s present React calls it after updating the state.

Now when a user triggers increaseScoreBy3(), React queues up the multiple functional setState. We won’t fake that logic here, as our focus is on what actually makes functional setState safeBut you can think of the result of that “queuing” process to be an array of functions, like this:

const updateQueue = [
  (state) => ({score : state.score + 1}),
  (state) => ({score : state.score + 1}),
  (state) => ({score : state.score + 1})
];

Finally, let’s fake the updating process:

// recursively update state in the order
function updateState(component, updateQueue) {
  if (updateQueue.length === 1) {
    return component.setState(updateQueue[0](component.state));
  }
return component.setState(
    updateQueue[0](component.state), 
    () =>
     updateState( component, updateQueue.slice(1)) 
  );
}
updateState(Justice, updateQueue);

True, this is not as so sexy a code. I trust you could do better. But the key focus here is that every time React executes the functions from your functional setState, React updates your state by passing it a fresh copy of the updated state. That makes it possible for functional setState to set state based on the previous state.

Here I made a bin with the complete code. Tinker around it (possibly make it look sexier), just to get more sense of it.

Play with it to grasp it fully. When you come back we’re gonna see what makes functional setState truly golden. Web development services in Hyderabad visit Vivid Designs 

The best-kept React secret

So far, we’ve deeply explored why it’s safe to do multiple functional setStates in React. But we haven’t actually fulfilled the complete definition of functional setState: “Declare state changes separately from the component classes.”

Over the years, the logic of setting-state — that is, the functions or objects we pass to setState() — have always lived inside the component classes. This is more imperative than declarative.

Well today, I present you with newly unearthed treasure — the best-kept React secret:

Thanks to Dan Abramov!

That is the power of functional setState. Declare your state update logic outside your component class. Then call it inside your component class.

// outside your component class
function increaseScore (state, props) {
  return {score : state.score + 1}
}
class User{
  ...
// inside your component class
  handleIncreaseScore () {
    this.setState( increaseScore)
  }
  ...
}

This is declarative! Your component class no longer cares how the state updates. It simply declares the type of update it desires.

To deeply appreciate this, think about those complex components that would usually have many state slices, updating each slice on different actions. And sometimes, each update function would require many lines of code. All of this logic would live inside your component. But not anymore!

Also, if you’re like me, I like keeping every module as short as possible, but now you feel like your module is getting too long. Now you have the power to extract all your state change logic to a different module, then import and use it in your component.

import {increaseScore} from "../stateChanges";
class User{
  ...
  // inside your component class
  handleIncreaseScore () {
    this.setState( increaseScore)
  }
  ...
}

Now you can even reuse the increaseScore function in a different component. Just import it.

What else can you do with functional setState?

Make testing easy!

You can also pass extra arguments to calculate the next state (this one blew my mind… #funfunFunction).

Expect even more in…

The Future of React

For years now, the react team has been experimenting with how to best implement stateful functions.

Functional setState seems to be just the right answer to that (probably).

Hey, Dan! Any last words?

If you’ve made it this far, you’re probably as excited as I am. Start experimenting with this functional setState today!

If you feel like I’ve done any nice job, or that others deserve a chance to see this, kindly click on the green heart below to help spread a better understanding of React in our community.

If you have a question that hasn’t been answered or you don’t agree with some of the points here feel free to drop in comments here or via Twitter.

Happy Coding!

Land Rover Discovery Sport Faclift Review & Test Drive

Land Rover Discovery Sport Overview

Land Rover has been putting in efforts to improve their product line up and lately have become more aggressive in the compact crossover segment. The result of this aggression is the new Discovery Sport. We checked out this new SUV from Land Rover, to get a feel of what it is all about. Land Rover has introduced the Discovery Sport with a 2.0-litre petrol engine. This engine produces 237bhp of power and comes with an eight-speed automatic transmission.  For information on contact details of Land Rover car dealers in New Delhi

For price details on Land Rover Discovery Sport check Carzprice

The Discovery Sport comes as a replacement for the Freelander2. At first glance, you will be excused for thinking it to be the Range Rover Evoque, as it looks identical from far, especially the front portion. Though the two share most of the underpinnings, there are many differences between the two. The major difference here is that the the Discovery Sport is a more rugged machine with better off-roading capabilities.

Land Rover Discovery Sport Exterior & Style

The Discovery Sport, unlike the Freelander 2 isn’t boxy, and that’s a welcome change. In fact, a quick glance at it is enough to figure that it draws some inspiration from the Range Rover Evoque. But amazingly, the Disco still manages make its own identity with its subtle design cues.

Look at the Discovery Sport from the front and it screams Land Rover. That smoothly carved out bonnet, and the honeycomb grille grill with the Discovery badge above it give it a clean look up front. And then adding a bit of spunk, there are those sweet looking circular daytime running lamps around the projector headlamps. We particularly liked the way the rear end coexists with the front thanks to certain elements in its design. The smoked tail lamp cluster too has circular LEDs and there’s the all important Discovery badge above the registration plate. Although the oddball rear design doesn’t look as evolved and butch as the front, the overall styling will surely grow on you over time.

Land Rover Discovery Sport Interior & Space

On the inside, the Discovery Sport is straight and simple. Purposeful, yet classy. It cannot be termed very premium but the build quality is solid and built to last. The finish in some areas does feel ordinary. The instrument cluster has twin dials and is lit in white, having a simplistic design. A new centre console comes in place and houses the gear dial which rises for use only when the ignition switch is activated. A new touchscreen infotainment system is seen in this SUV which is easy to operate even while driving, however, it takes time getting used to the interface .The driving position is not very tall but near perfect, and offers good visibility. The seats are firm, well contoured and comfortable. The seats also have electric adjustments. The vehicle over all is pretty spacious and has air vents for all rows. The huge panoramic glass roof further makes it feel spacious. The unique thing here is that every passenger gets a USB charging point which makes it a total of seven USB ports.

The Discovery Sport is slightly longer than the Freelander 2 and hence it also comes as a seven-seater option. Hence it makes this compact SUV a good option for a larger family. But its only the kids who can occupy the third row comfortably . The seven-seat version gets a space saving spare tyre instead of the full-size spare which is found on the standard five-seat version.

Land Rover Discovery Sport Engine & Gearbox

There is only two engine options on the Discovery Sport – both use the same 2.0-litre turbocharged four-cylinder diesel unit, producing two outputs – 148bhp and 177bhp.

However, our test car used Ford-derived 2.2-litre diesel and the Sport’s most noticeable connection to the past is unmistakably that engine, which currently shadows everything the car does with the clatter and gunsmoke odour of yesteryear. Denying the car the new four-cylinder Ingenium oil-burner from launch was clearly the model’s on-paper Achilles heel and, to a greater or lesser extent, that’s the way it plays out on the road.

However, although the direct-injected 2.2-litre motor is not a paragon of refinement or efficiency, its later-life development has at least ensured that it produces the unmistakable surge expected of a modern blower-equipped diesel.

On stream, its 310lb ft of torque is a plentiful amount, and it feels that way. For a car that tipped the scales on the wrong side of two tonnes when we weighed it, a sub-9.0sec 0-60mph time is very decent. So is the 9.0sec it takes to get from 30mph to 70mph, very slightly bettering the time we recorded for the much-admired 2.2-litre engine in the Mazda CX-5 a couple of years ago.

In fact, the soft underbelly of the package is at times evident less in the 20th century motor and more in the 21st century gearbox to which it has been shackled.

Rather inevitably, the nine-speed automatic transmission’s keenness to keep the engine spinning at its productive mid-range pitch means that you’re going to have to live with a lot of downshifting – particularly on the motorway, where the never-ending 47.5mph per 1000rpm final ratio cannot be trusted with even modest acceleration.

Land Rover Discovery Sport Driving Dynamics

Driving in city or the highway you won’t run out of steam. There is sufficient grunt in the engine and makes it easy to drive. Ideally drive it in D mode, the S mode is when you want to sprint ahead but the difference isn’t anything major. In D the engine is comfortable as it is mostly in its power band and this is sufficient to drive.

The ride quality of the Discovery Sport is composed and pliant. This SUV glides over potholes with a hint of stiffness that can be left. All the due credit goes to the engineering team. Drive on bad roads and you won’t complain much. The suspension set up is balanced and doesn’t feel rough or unsettled. The chassis too is stiffer and the alacrity is much better. There is hardly any body roll when compared to the Freelander2 and this is at par with the German rivals. The steering wheel is light and convenient to drive on city and it starts to weigh up once the speed increases. There is nothing to complain in this department. There are multiple off-roading modes as well. These are nearly placed on the centre console freeing up space for more stowage.

Land Rover Discovery Sport Safety & Security

The Land Rover Discovery Sport sets the standard for safety in its class and achieved the full five stars in Euro NCAP’s crash tests. An airbag springs up from the top of the bonnet to help reduce head injuries in the case of a pedestrian collision, while interior airbags include one for the driver’s knee, as well as airbags that cover the head, chest and side areas of those up front. There are head and side airbags for passengers in the middle row of seats, too.

An automatic emergency braking system and lane departure assist are other standard features that don’t feature on all rivals. Traffic sign recognition, which displays the speed limit, is optional on all but base SE trim.

Land Rover Discovery Sport Price in Chennai

Land Rover Discovery Sport Ex-Showroom Price in Chennai ranges from 42,46,997/- (Discovery Sport 2.0l Diesel Pure 5 Seats) to 52,29,484/- (Discovery Sport 2.0l Diesel HSE Luxury 5 Seats). Get best offers for Land Rover Discovery Sport from Land Rover Dealers in Chennai. Check for Discovery Sport price in Chennai at Carzprice

Land Rover Discovery Sport Bottomline

Should you buy one then? The biggest draw is clearly the prestigious Land Rover badge. And then, there are a lot of options available in the market at that price point including its cousin – the Range Rover Evoque. Moreover when you consider the fact that its arch rivals offer a more powerful motor, then things get slightly more difficult. But then if you want a car that looks good, handles well, is practical and most importantly can take the road unexplored without breaking a sweat then the Land Rover Discovery Sport surely should be on your list.