HTML Preprocessor

This tutorial aims to elucidate HTML preprocessors and offer insight into their utilization. The HTML preprocessor, identified on the HTML page, serves as the first phase in the compilation process, encompassing tasks such as header inclusion, macro expansion, and comment removal. At times, repetitive tasks in HTML and CSS coding can lead to inefficiencies, a challenge that HTML preprocessors effectively address.

A preprocessor is a software application that takes input in a specific format and converts it into another format, often HTML and CSS. Its purpose is to smoothly incorporate additional functionalities while maintaining compatibility with various web browsers.

Following is the justification for the preprocessor addition:

✅ As per the DRY principle, we can reuse the same functionality without having to write or repeat a block of code repeatedly. The dry principle acronym of the Don't Repeat Yourself.
✅ Large-scale code will make it simpler to maintain the web page.
✅ Helps us correctly organize the code and cuts down on the total amount of time spent developing.

Frequently Used HTML Preprocessors

The html preprocessor is similar to html language with some syntax differences. Some of the most popular HTML preprocessors are listed below with detailed information.

✅ Haml
✅ Slim
✅ Handlebars
✅ Nunjucks

Pug Preprocessor

Pug, formerly recognized as the Jade processor, serves as a preprocessor that simplifies the creation of extensive HTML code. It provides a wide range of features, including conditionals, loops, mixins, JavaScript objects, and templates.

Benefit:

✅ Clean Syntax: Jade stands out for a number of reasons, including its streamlined syntax.
✅ The JavaScript detail selector library, your fashion sheet, and the template are all constant since elements are formed using the CSS selector syntax.
✅ Reusability: Scala, PHP, Ruby, Python, JavaScript, and Java can work with Jade templates.

Disadvantages

✅ The structure is dependent on proper indentation. Errors in indentation can negatively impact the final result, requiring significant time and effort to rectify.
✅ Collaborative coding can lead to issues with inconsistent formatting when each team member employs a unique indentation scheme. This can complicate tasks like copying, pasting, or reorganizing code.

Examples

The example displays Pug code and HTML code side by side. Pug does not require opening and closing tags, making it more concise compared to HTML.

Example 1:

The provided example demonstrates a fundamental pug and HTML coding structure. Both the HTML and pug preprocessor exhibit identical code along with the corresponding result.

In the pug coding template, a straightforward expression is depicted in the syntax.

Example


<!-- pug template code -->
doctype html
html
head
title  Welcome to the pug preprocessor
body
h1  Welcome to the pug preprocessor
h3  the pug preprocessor shows easy and simple syntax

✅ html coding template

Example


<!--HTML code -->
<!DOCTYPE html>
<html>
<head>
<title> Welcome to the pug preprocessor </title>
</head>
<body>
<h1> Welcome to the pug preprocessor </h1>
<h3> The pug preprocessor shows easy and simple syntax </h3>
</body>
</html>

Output

The image shows the output of the preprocessor.

Example 2:

The illustration demonstrates a fundamental pug and HTML coding framework paired with CSS. The identical code is presented for both HTML and the Pug preprocessor, showcasing the final design, color scheme, and background color.

The Pug coding template exhibits a straightforward expression incorporating the style property in its syntax.

Example


<!--pug code -->
doctype html
html
head
title  Welcome to the pug preprocessor
style.
h1{
color: orange;
}
h3{
color:aqua;
}
body(style='background-color: lightgrey;')
h1  Welcome to the pug preprocessor
h3  the pug preprocessor shows easy and simple syntax

✅ html coding template

Example


<!--HTML code -->
<!DOCTYPE html>
<html>
<head>
<title> Welcome to the pug preprocessor </title>
<style>
h1{
color:orange;
}
h3{
color:aqua;
}
</style>
</head>
<body style="background-color: lightgrey;">
<h1> Welcome to the pug preprocessor </h1>
<h3> The pug preprocessor shows easy and simple syntax </h3>
</body>
</html>

Output

The image shows the output of the preprocessor.

HAML Preprocessor:

Haml is an acronym for HTML Abstraction Markup Language, created by Hampton Catlin to enhance the visual appeal of markup. This preprocessor, reliant on Ruby, necessitates the presence of Ruby on the system. An HTML preprocessor can be viewed as a utility to assist developers in translating the preprocessor's syntax into HTML syntax seamlessly. Notably, Haml introduces unique elements not found in standard HTML syntax.

Haml prohibits the inclusion of inline code in web content. It streamlines HTML structure and permits the inclusion of specific dynamic elements. Preprocessors are tools designed to always interpret code in a particular language, leading to the utilization of HTML and Sass in handling Haml.

The popularity of preprocessors has resulted in the development of numerous frameworks to enhance their functionality, with Compass standing out as a highly favored option.

Benefit

✅ The advantage of hamlet learning lies in its straightforwardness thanks to the plethora of online resources available.

Drawback:

✅ Haml uses indentation rather than closing tags to indicate structure.
✅ This can occasionally lead to issues that make writing code more efficient in some circumstances.
✅ Making changes in a single place has the potential to break the code's structure or result in an error.
✅ Haml has a slower rendering time compared to its competitors.

Examples

The given illustration displays both Haml preprocessor code and HTML code. Unlike HTML, Haml does not require opening and closing tags, yet its syntax closely resembles that of HTML.

Example 1:

The illustration demonstrates the fundamental HTML and html code template. Both the html and Haml preprocessor exhibit identical code along with the result.

In the HAML code template, a straightforward expression is displayed in the syntax.

Example


!!!
%html
  %head
    %meta{:content => "text/html; charset=UTF-8", "http-equiv" => "Content-Type"}/
    %title Welcome to the HAML preprocessor
  %body
    %h1 Welcome to the HAML preprocessor
    %h3 The HAML preprocessor shows easy and simple syntax

✅ html coding template

Example


<!DOCTYPE html>
<html>
<head>
<title> Welcome to the HAML preprocessor </title>
</head>
<body>
<h1> Welcome to the HAML preprocessor </h1>
<h3> The HAML preprocessor shows easy and simple syntax </h3>
</body>
</html>

Output

The image shows the output of the preprocessor.

Example 2:

The illustration highlights a fundamental HTML and html code structure paired with CSS. The identical code is demonstrated for both HTML and the Haml preprocessor, showcasing the resultant design, color scheme, and background color.

In the Haml coding template, the straightforward expression featuring the style attribute is depicted in the syntax.

Example


!!!
/ HTML code
%html
  %head
    %meta{:content => "text/html; charset=UTF-8", "http-equiv" => "Content-Type"}/
    %title Welcome to the HAML preprocessor
    :css
      h1{
          color: orange;
      }
      h3{
          color: aqua;
      }
  %body{:style => "background-color: lightgrey;"}
    %h1 Welcome to the HAML preprocessor
    %h3 The HAML preprocessor shows easy and simple syntax

✅ html coding template

Example


<!--HTML code -->
<!DOCTYPE html>
<html>
<head>
<title> Welcome to the HAML preprocessor </title>
<style>
    h1{
        color: orange;
    }
    h3{
        color: aqua;
    }
</style>
</head>
<body style = "background-color: lightgrey;">
<h1> Welcome to the HAML preprocessor </h1>
<h3> The HAML preprocessor shows easy and simple syntax </h3>
</body>
</html>

Output

The image shows the output of the preprocessor.

Slim Preprocessor

Slim is a templating language designed to simplify view syntax by removing unnecessary elements while maintaining clarity. The initial concept was to streamline a standard HTML template to its core components.

Benefit:

✅ The Slim syntax is easy to read because it only requires a few special symbols.
✅ It is easy for humans who have never worked on it before on a template. The syntax is incredibly simple and legible.
✅ Slim's documentation is well-organized and comprehensive, and each concept is clearly stated.
✅ It is quite helpful for all customers, including those who are new to using the template.
✅ The Slim is minimalist to start and learn the template. It may be easily expanded, and it can even support well-known Laravel applications.
✅ It enables the creation of code rapidly and makes it available for experimenting or messing around the code.
✅ It is helpful in the event that you need an auto-close or auto-complete plugin.

Drawback:

✅ Those unfamiliar with this syntax may perceive Slim as unconventional due to its utilization of capitalization and absence of HTML tags.

Examples

The example demonstrates the slim preprocessor template alongside the HTML template. Slim preprocessor simplifies the need for both opening and closing tags, offering a straightforward approach to comprehend the HTML syntax.

Example 1:

The demonstration illustrates the fundamental syntax of the slim preprocessor and an HTML coding template. The code for both the HTML and slim preprocessor is provided along with the resultant output.

The template for the slim preprocessor displays a straightforward expression in its syntax.

Example


doctype html
html
  head
    title
      |  Welcome to the Slim preprocessor 
  body
    h1
      |  Welcome to the Slim preprocessor 
    hr
    h3
      | The Slim preprocessor shows easy and simple syntax 
    section
      i
        |  Home Web Page

A fundamental HTML template displays the HTML element and tag structure.

Example


<!DOCTYPE html>
<html>
<head>
<title> Welcome to the Slim preprocessor </title>
</head>
<body>
<h1> Welcome to the Slim preprocessor </h1>
<hr>
<h3> The Slim preprocessor shows easy and simple syntax </h3>
<section>
<i> Home Web Page </i>
</section>
</body>
</html>

Output

The image shows the output of the preprocessor.

Example 2:

The illustration demonstrates a fundamental slim and html coding structure incorporating JavaScript and CSS. The identical code is presented for both the html and slim preprocessors showcasing validation, layout, color schemes, and background color.

✅ In the Slim preprocessor template, the syntax displays a concise expression with the style attribute.

Example


doctype html
html
  head
    title
      |  Welcome to the slim preprocessor 
    style
      |  h1{ color: orange; } h3{ color: Red; } 
    script
      |  function myProcess() { alert("Hello! I am an Html Preprocessor"); } 
  body[style="background-color: #FFFF8A;"]
    h1
      |  Welcome to the slim preprocessor 
    h3
      | The Slim preprocessor shows easy and simple syntax 
    button[onclick="myProcess()"]
      |  Click Here!!!

This HTML coding template provides a foundational structure, displaying the basic HTML layout alongside the CSS style tag.

Example


<!--HTML code -->
<!DOCTYPE html>
<html>
<head>
<title> Welcome to the slim preprocessor </title>
<style>
    h1{
        color: orange;
    }
    h3{
        color: Red;
    }
</style>
<script>
function myProcess() {
  alert("Hello! I am an Html Preprocessor");
}
</script>
</head>
<body style = "background-color: #FFFF8A;">
<h1> Welcome to the slim preprocessor </h1>
<h3> The Slim preprocessor shows easy and simple syntax </h3>
<button onclick = "myProcess()"> Click Here!!! </button>
</body>
</html>

Output

The image shows the output of the preprocessor.

Handlebars Preprocessor

Handlebars preprocessor offers the essential capability to assist you in generating meaningful templates efficiently and with ease.

Benefit:

✅ Logic-less templates force you to divide concerns through layout, which helps you avoid future refactoring problems.
✅ It also allows templates to be used unchanged with multiple programming languages.
✅ The Handlebars is available as a Django module and a JavaScript library with the Java, Ruby, Scala, and PHP libraries.
✅ This implies using it for templates in the language you want for both frontend and backend applications.

A drawback associated with text editors for handlebars is the limited availability of advanced functionalities such as syntax highlighting, auto-complete, and error checking.

Example

The subsequent illustration illustrates the fundamental syntax or template of the handlebars preprocessor. In this case, the preprocessor is employed to showcase the user's given name and surname.

Template of the Handlebars expressions

Example


<p>{{firstname}} {{lastname}}</p>

It applies the input object in the json format.

Example


input
{
  firstname: "mruna",
  lastname: "sharma",
}

The output shows the user name and its tag.

Example


<p> mruna sharma </p>

Nunjucks preprocessor

The token-driven method integrates various functionalities like iteration, conditional statements, and data manipulation provided by multiple engines. It also offers several advanced components for webpage structuring, such as includes, block inheritance, style inheritance, custom tags, and macros. These elements are particularly beneficial for a content management system (CMS) that often constructs pages using a modular approach.

Benefit:

✅ Async assistance
✅ Widespread format inheritance
✅ Support for macros
✅ The simple old-fashioned college comprises
✅ Support for filters
✅ control of the white space in coding
✅ Utilising unquestionably HTML, with little to no white space
✅ Used for things other than HTML, such as JSON and configuration files.
✅ Support for custom tags

Downside

The lack of support for streaming operations

Benefits and Drawbacks of HTML Preprocessor Use

Let's explore the advantages and disadvantages of using preprocessors.

Benefits

✅ It simplifies the appearance of our code. It makes it simpler for programmers to read and comprehend.
✅ The code appears better because it is properly indented.
✅ Preprocessors mostly use the DRY or Don't Repeat Yourself thing to prevent code from being repeated.

Drawbacks:

✅ Text editors that include preprocessors are not commonly found, making them less popular among developers.
✅ Issues with indentation can negatively impact the outcomes, often stemming from the practice of copying and pasting code.

Conclusion

The HTML preprocessor describes the transformation of a data type into another. Commonly used HTML preprocessors include Nunjucks, Handlebars, Pug, Slim, and Haml. Haml serves as a substitute for PHP and various other templating technologies. Pug provides features like conditionals, loops, mixins, templates, and JavaScript objects.

Slim aims to simplify view syntax while maintaining clarity and avoiding complex transformations. Handlebars empowers users to swiftly and effortlessly craft semantic templates. Collaborating on templates and integrating advanced functionalities such as localization is straightforward with Nunjucks.

Frequently Used HTML Preprocessors

Pug Preprocessor

HAML Preprocessor:

Slim Preprocessor

Handlebars Preprocessor

Nunjucks preprocessor

Benefits and Drawbacks of HTML Preprocessor Use

Conclusion

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