Creating an ES6 Function that accepts infinite Arguments with Example

Hello, Friends here in this article I will be teaching you to create an calculate function that can take any number of arguments thrown by the user.

If you are creating a function that can take any number of arguments that function has a name called
Variadic functions.

Variadic Functions: Functions are called Variadic when they take an indefinite number of arguments when calling.

Let's go back when ES6 has not introduced the developers were very confused. They were using the Arguments object to implement this feature.

What is the Arguments Object?

Arguments object is the array like object which has length property but not all the methods of the  Array. This object is present in all non-arrow functions as the local variable.

Similar to Array the function's arguments are arranged indexed from zero Arguments object.

Today I will show you to create a variadic function that can accept any number of arguments. using two methods.

1. Using Arguments Object
2. Using the ES6 Rest Parameter.

Let's Create Calculate Function Using the Old Arguments Function and discuss its pros and cons.

The Second one is optional here you have to specify the index position to starts searching from.

Simple Calculate Function Using Arguments Object:

See the Pen Creating variadic function using arguments object by MD M Nauman (@mmnauman) on CodePen.

Check the above calculate function in this we are not passing any parameter instead of that we are using the local arguments object that store all the arguments for us.

We know that Arguments object is similar to an array but does not have array methods like forEach, map etc.

We have used for of loop to loop the arguments object and to get the sum of all the numbers we have used a variable called num whose value is 0 which is global.

We have used the num variable to add the numbers of the arguments object. then we return the num variable.

We have also used the arguments object built in property which is the length to get the number of arguments.

After that, we have added it to the body with some basic styling.

Why we should not use arguments object?

1. The Function we have created above does not have any parameter. This will be misleading for the users as in the heading we are saying it accepts infinite arguments but when they see it it doesn't have any parameter.
2. Very Confusing for the newbie developers too as they don't know from where the hell this arguments object is coming.

Now I will show you the next and recommended way of doing this task. As of now, the ES6 has become the new standard of JavaScript for coding. Now, most modern browsers support this feature which is known as Rest Parameter.

Rest Parameter (...parameter) :

Rest Parameter is an Array that is made to accept an infinite or indefinite number of arguments. You can think it as an empty box that can store any number of values.

Rest Parameter is an Array this meant all the array methods can be used like forEach, map, filter etc

Rest Parameter starts with three consecutive dots ... then the name of the parameter. The name which you have given after the prefix that only will become the Rest Parameter. There are no naming restrictions like we see in the arguments object.

Let's Create Calculate Function Using the ES6 Rest Parameter and discuss its pros and cons.

See the Pen Creating variadic function using Rest Parameter by MD M Nauman (@mmnauman) on CodePen.

Check the above calculate function in this we are passing the parameter. That parameter, when used with the three dots, will become Rest Parameter and become the array that store all the arguments.

We know Rest Parameter is an Array so all the array methods like map, filter, forEach will work.

We have used the forEach Method to loop the arguments and to get the sum of all the numbers.

 We have used a variable called num whose value is 0 which is global.

We have used the num variable to add the numbers of the arguments object. then we return the num variable.

We have also used the Array built-in property which is the length to get the number of arguments.

After that, we have added it to the body with some basic styling.

Why we should use Rest Parameter over arguments object?

1. The Rest Parameter is an array so the array methods will be available for use.
2. When we created the function we have used the parameter with the three dots that indicate that we are using this Rest Parameter. By using this parameter user will know that it can accept an indefinite number of arguments.
3. This is The ES6 way of doing so we will stick to it.

Conclusion

I have shown you both the ways to create the variadic function. I have also explained to you which to use and why. You can use the old way also but we should always update ourselves.

Try to practice this functions and create apps like calculator, bill creator etc.

That's It, Thanks For Following our Tutorial ''Creating an ES6 Function that accepts infinite Arguments with Example' If you found any difficulty following along with me. Please Comment and Share Your Valuable Opinion. And Stay tuned for More Tutorials Like This and Share this with your friends.

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Brand New JavaScript ES6 String Methods that you should Know?

Hello, Friends, I know most of the developers are now switching to es6 or they have already switched.

ES6 looks little complicated but it is easy at last now javascript also possessing all the features similar to python etc

I'm writing this article to show you a few powerful string methods that we developers got as a gift from the ES6.

String methods like trim(), the index based accessing etc are very popular now which was introduced in the ES5 (ECMAScript 5)

Today I will show you three new string methods that are introduced with ES6. They are as follows

1. startsWth()
2. endsWith()
3. repeat()

The above are the three new string methods.  I will explain them with an example one by one starting from the top to bottom.

startsWith(): This method is case sensitive. this method accepts two parameters. First one is required and the second one is optional.

Syntax:

let example = "Hello, Developer. How are you?";
example.startsWith(searchString , position);

This method returns boolean true or false. if your search matches the string starting characters then it will return true otherwise false.

Arguments: 

The First one is Required *. Here you have to add the starting characters of the string that you are searching.

The Second one is optional here you have to specify the index position to starts searching from.

Example of a startsWith method:

See the Pen String Methods in ES6 by MD M Nauman (@mmnauman) on CodePen.

This was the simple example of a startsWith method. You can add the second parameter to specify the index position to starts searching from there.

The used case of startsWith:

It can be used in many things from filtering out the names based on their first name,

You can also allow only people whose name starts with certain characters to login in your site or do some other stuff.

There are so many things that can be done using this method.

It will replace complex regex methods to find with a certain pattern.

Play with this in your developer tools to get the instant return value.

endsWith(): This method also possesses similar features that we saw above in startsWith method.

This method is case-sensitive. It also accepts two parameters.

The first Parameter is required and the second one is optional.

Syntax:

let example = "Hello, Developer. How are you?";
example.startsWith(searchString , length);

This method returns boolean true or false. if your search matches the string starting characters then it will return true otherwise false.

Arguments: 

The First one is Required *. Here you have to add the starting characters of the string that you are searching.

The Second one is optional. This second parameter is different than the startsWith method. Here you have to specify the length of the string within that you want to search your characters.

Example of an endsWith method:

See the Pen String Methods in ES6 endsWith() by MD M Nauman (@mmnauman) on CodePen.

The used case of endsWith() Method:

This is a very powerful string method and can be used in many things like:

To find out the emails ending with .com, .net etc

To find out whether the person last name is 

To find out whether the  image is jpg/png etc

There are many possibilities you can implement this method in your projects. 

repeat(): This method creates copies of the string and you have to specify the number as the argument to create your desired amount of copies. This method doesn't modify the original string but it will return the new string with the specified copies of the string.

repeat method accepts one parameter. The Parameter is required

Syntax:

let example = "Hello";
example.repeat(5);

Arguments: 

The argument is Required *. Here you have to add the number so that the repeat method will create that many copies of the string for you.

Example of the repeat method:

See the Pen String Methods in ES6 repeat() by MD M Nauman (@mmnauman) on CodePen.

The used case of repeat Method:

This method is rarely used as it is not that useful.

You can use this method in your development to generate dummy text.

Conclusion

I'm concluding this article now. This is the brand new methods that were introduced with ES6. If you found it little difficult then try it again and again till you get used to with them.

With this new methods, I think the development complexity will be reduced. More then that javascript is becoming powerful day by day.

ES6 is a new standard for JavaScript. Leaving Internet Explorer most modern browsers support all these methods. and gradually all browsers have to comply with this standard.

That's It Thanks For Following our Tutorial ''Brand New JavaScript ES6 String Methods that you should Know?' Along With us If you found any difficulty Please Comment and Share Your Valuable Opinion. And Stay tuned for More Tutorials Like This and Share this with your friends.

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Email Subject Line Research 2018: Short is the Latest Trend

We’ve taken a comprehensive look at all emails and associated data sent last year to gain new insights into the importance of subject lines. The aim of this is to learn more about how to get emails open, read, and converting. By taking all of the data available we’ve been able to draw up a list of key questions that we intend to answer in this article.

1. Does Personalization Improve Open Rates?

In this instance, personalization refers to adding the person’s first name to the subject line. There is always the option to add the full name, but this can often appear too formal and is not appropriate.

The key thing to understand is that whilst personalized subject lines may seem like a nice touch, do they actually improve the open rate?

Personally, I feel that personalized subject lines run the risk of appearing spammy. As a recipient, I know that I am receiving an automated email, which makes the use of my first name feel insincere and not genuine.

Interestingly, when we began to crunch the numbers we found that only 3.5% of emails sent actually employed a personalized subject line. We then saw that the open rate for emails using a personalized subject line was 18.1%, as compared to the open rate of 17.9% for non-personalized emails. This is not a statistically significant difference as a larger sample could see the difference reversed.

It is clear that the data shows personalization has no demonstrated impact on open rates.

2. Do Exclamation Marks Add Emphasis, Or Reduce Conversions?

After compiling the top 30 performing subject lines used with newsletters we noticed that 14 of them contained exclamation marks.

By looking at newsletter campaigns and automated email workflows we were able to investigate whether their inclusion had any impact on conversion rates.

A. Newsletter Campaigns
42% of email subject lines contained exclamation marks, so how did this translate into conversions?

Subject lines that didn’t use exclamation marks had an open rate of 18%, as compared to 17% for subject lines using exclamation marks.
Interestingly there was also a negative correlation between open rates and the number of exclamation marks. With one exclamation mark, the open rate was 17.5%, falling to 16.7% for 2 exclamation marks, and16.5% for 3 exclamation marks or more. A clear sign from the data that users are put off by the use of exclamation marks.

B. Automation Workflows:

We found that a total of 95% of all automated emails sent by Omnisend marketers used exclamation marks.

Interestingly a single exclamation mark leads to an open rate of 29%, whilst multiple exclamation marks caused the open rate to increase to 35%. 

It’s important to understand that the sample size for multiple exclamation marks was far smaller and was therefore far more susceptible to being easily biased. 

There are also take-home points to be learned from looking at single emails and sequences of emails separately. 

Single Automated Email: Emails with a single exclamation mark achieved a 47% open rate. This then fell steeply to 42% when multiple exclamation marks were used.

It’s important to understand that the multiple exclamation samples were only 0.7% of the total sample size. 

Automated Email Series: The use of a single exclamation mark resulted in an open rate of 24%,  2 or more saw a drop to 21%.

This tells us that if you’re creating an email sequence then you will see a drop off in open rates when using multiple exclamation points. There are a number of possible reasons for this, such as reduced confidence that the message isn't spammed, but the numbers don’t lie. 

3. Should You Offer Discounts in Dollar Amounts or as Percentages?

At Omnisend we’re regularly asked about the best way to offer a discount. Should it be as a dollar amount (save $15) or as a percentage (get 15% off)? 

To gain some fresh insight into this problem we looked at subject lines containing a $ sign and compared them with those containing a % sign. Here’s what we found.

Interestingly the % sign was 10 times as popular amongst the marketers we looked at, but this didn’t translate into better performance. The dollar sign was underutilized and yet it leads to a higher open rate.

The open rate for $ sign subject lines was 29%, which was 4 percentage points higher than the 25% achieved by % sign subject lines. Proof that it pays to tell people the absolute amount of money they will be saving, rather than focusing their attention on margins.  

4. What is the Length of the Ideal Subject Line?

Interestingly we found that one of the biggest brands in our survey had a tendency to use very long subject lines.

We found that most subject lines used on average 11-50 characters, but why? Is this the most effective length? Or does the brand using over 200 characters on a regular basis know something that everyone else has missed?

Take a look at the graph below which charts open rates and include a curve showing which are the most commonly sent subject line lengths. 

Interestingly you see that longer is better, to an extent. Subject lines with 51-90 characters show a 40.5% open rate, whilst the more commonly sent 11-50 character subject lines achieve a much lower open rate of 33.8%.

It is again important to take into account sample size and the ease of biasing. The red curve clearly shows that the size of the sample for the 51-90 character subject lines is significantly smaller and therefore more likely to be skewed. 

To get specific, it is seen that subject lines with 21-30 characters achieve the highest open rates. 

Indicating that short is the latest trend there is probably no need to regularly send long subject lines if you want to maximize the open rate of your emails. 

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