Module 5: CSS Preprocessor PDF

Programme Name: Bachelor of Computer Applications Course Name: HTML,CSS and CSS preprocessors (BCA20002) Class: BCA 2nd Semester Academic Session: 2023-24 Study Material HTML, CSS AND CSS Preprocessor (BCA20002) Module 5: CSS Preprocessor SASS: Syntactically Awesome Style Sheet. Learner style shee...

Programme Name: Bachelor of Computer Applications Course Name: HTML,CSS and CSS preprocessors (BCA20002) Class: BCA 2nd Semester Academic Session: 2023-24 Study Material HTML, CSS AND CSS Preprocessor (BCA20002) Module 5: CSS Preprocessor SASS: Syntactically Awesome Style Sheet. Learner style sheet, stylus, designing frontend. Table of Contents: Topic Topic Page no. number 1 CSS Pre-processor 1-5 2 Benefits of using CSS pre-processors 5-6 3 Popular CSS pre-processors 7-8 4 Basic Concepts 8-11 5 Tooling and Workflow 11-13 6 Integrating pre-processors with build 13.15 tools (e.g., Webpack, Gulp) 7 Using command-line compilers 16-18 8 Benefits of Using Command-Line 18 Compilers: CSS Preprocessor The syllabus for learning CSS preprocessors such as Sass, LESS, or Stylus typically covers a range of topics to help you understand the fundamentals and advanced concepts of using these tools effectively. Here's a comprehensive syllabus outline: 1. Introduction to CSS Preprocessors a) What is a CSS preprocessor? b) Benefits of using CSS preprocessors c) Popular CSS preprocessors: Sass, LESS, Stylus d) Setting up your development environment Dept. of Computational Sciences 1|Page Brainware University, Kolkata Programme Name: Bachelor of Computer Applications Course Name: HTML,CSS and CSS preprocessors (BCA20002) Class: BCA 2nd Semester Academic Session: 2023-24 2.Basic Concepts a) Variables b) Nesting c) Mixins d) Functions e) Operations f) Control directives (e.g., @if, @for, @each) 3.Advanced Features a) Partials and @import b) Extend/Inheritance c) Placeholder selectors d) Built-in functions e) Interpolation f) Importing external libraries 4. Tooling and Workflow a) Integrating preprocessors with build tools (e.g., Webpack, Gulp) b) Using command-line compilers c) Automating tasks with preprocessors (e.g., watch, compile) d) Debugging techniques 5. Best Practices a) Organization and structure of code b) Reusability and maintainability c) Performance considerations d) Code optimization Dept. of Computational Sciences 2|Page Brainware University, Kolkata Programme Name: Bachelor of Computer Applications Course Name: HTML,CSS and CSS preprocessors (BCA20002) Class: BCA 2nd Semester Academic Session: 2023-24 6. Advanced Topics a) Modular architecture and component-based styling b) Responsive design with preprocessors c) Theming and variable management d) Integrating preprocessors with CSS frameworks (e.g., Bootstrap, Foundation) e) Performance optimization techniques 7. Project Work a) Building small to medium-sized projects using preprocessors b) Converting existing CSS codebases to use preprocessors c) Implementing advanced features in projects d) Collaborative projects to apply learned concepts in a team setting 8. Resources and References a) Official documentation of the chosen preprocessors b) Online tutorials, articles, and blogs c) Books on CSS preprocessors d) Community forums and discussion groups e) Hands-on coding exercises and challenges 9. Assessment and Evaluation a) Regular quizzes and assignments b) Coding exercises and projects c) Peer code reviews d) Final exam or project presentation Dept. of Computational Sciences 3|Page Brainware University, Kolkata Programme Name: Bachelor of Computer Applications Course Name: HTML,CSS and CSS preprocessors (BCA20002) Class: BCA 2nd Semester Academic Session: 2023-24 Introduction to CSS Preprocessors ⮚ What is a CSS Preprocessor ? CSS Preprocessors are increasingly becoming a mainstay in the workflow of front end web developers. CSS is an incredibly complicated and nuanced language, and in an effort to make its usage easier, developers often turn to using preprocessors such as SASS or LESS. CSS Preprocessors compile the code which is written using a special compiler. They then use that to create a CSS file, which can then be referenced by the main HTML document. Dept. of Computational Sciences 4|Page Brainware University, Kolkata Programme Name: Bachelor of Computer Applications Course Name: HTML,CSS and CSS preprocessors (BCA20002) Class: BCA 2nd Semester Academic Session: 2023-24 When using any CSS Preprocessor, you will be able to program in normal CSS just as you would if the preprocessors were not in place. The good thing is you also have more options available to you. Some, such as SASS, has specific style standards which are meant make the writing of the document even easier, such as the freedom to omit braces if you want. Of course, CSS Preprocessors also offer other features as well. Many of the features offered are incredibly similar across preprocessors, with only slight variances in syntax. Thus, you can choose pretty much any one you wish, and you will be able to achieve the same things. Some of the more useful features are: Variables One of the most commonly used items in any programming language is the variable, something which CSS notably lacks. By having variables at your disposal, you may define a value once, and reuse if throughout the entire program. An example of this in SASS would be: $yourcolor: #000056.yourDiv { color: $yourcolor; } By declaring the SASS yourcolor variable once, it is now possible to reuse this same exact color throughout the entire document without ever having to retype the definition. Benefits of using CSS preprocessors Nesting: Preprocessors support nesting of CSS rules, mirroring the HTML structure of the document. This improves readability and reduces redundancy by avoiding repetition of parent selectors. Mixins: Mixins are reusable blocks of styles that can be included within other styles. They enable developers to define complex styles once and reuse them throughout the stylesheet, reducing code duplication. Dept. of Computational Sciences 5|Page Brainware University, Kolkata Programme Name: Bachelor of Computer Applications Course Name: HTML,CSS and CSS preprocessors (BCA20002) Class: BCA 2nd Semester Academic Session: 2023-24 Functions: Preprocessors often provide built-in or custom functions for manipulating values within stylesheets. Functions can be used for calculations, color manipulation, and other advanced styling tasks, enhancing flexibility and expressiveness. Partials and Importing: Preprocessors allow stylesheets to be broken into smaller, modular files called partials. These partials can then be imported into the main stylesheet, promoting code organization and reusability. Extend/Inheritance: Preprocessors offer mechanisms for extending existing CSS rules or creating rule inheritance. This helps to avoid repetition and keep styles DRY (Don't Repeat Yourself), leading to cleaner and more maintainable code. Vendor Prefixing: Some preprocessors automatically generate vendor prefixes for CSS properties, ensuring cross-browser compatibility without manual intervention. Advanced Features: Preprocessors provide additional features such as conditionals, loops, and advanced calculations, enabling more dynamic and flexible stylesheet authoring. Tooling and Workflow: Preprocessors integrate seamlessly with build tools like Webpack or Gulp, allowing for automated compilation, minification, and other optimizations. They also support a faster development workflow by providing features like live reloading and error checking. Community and Ecosystem: CSS preprocessors have vibrant communities and extensive ecosystems, with numerous plugins, frameworks, and resources available to aid developers in their styling efforts. Dept. of Computational Sciences 6|Page Brainware University, Kolkata Programme Name: Bachelor of Computer Applications Course Name: HTML,CSS and CSS preprocessors (BCA20002) Class: BCA 2nd Semester Academic Session: 2023-24 ⮚ Popular CSS preprocessors: Sass, LESS, Stylus Sass (Syntactically Awesome Stylesheets) Sass is one of the most widely used CSS preprocessors, known for its powerful features and robust ecosystem. It introduces a more concise and expressive syntax compared to traditional CSS, with features like variables, nesting, mixins, functions, and inheritance. Sass offers two syntax options: SCSS (Sassy CSS), which uses a syntax similar to CSS with curly braces and semicolons, and Sass (indented syntax), which uses indentation instead of curly braces and semicolons. It has a large community, extensive documentation, and many third-party libraries and frameworks built on top of it. LESS: LESS is another popular CSS preprocessors that shares many similarities with Sass. It offers features such as variables, nesting, mixins, and functions, making CSS authoring more efficient and maintainable. LESS syntax closely resembles CSS, which can make it easier for developers already familiar with CSS to transition to using LESS. Dept. of Computational Sciences 7|Page Brainware University, Kolkata Programme Name: Bachelor of Computer Applications Course Name: HTML,CSS and CSS preprocessors (BCA20002) Class: BCA 2nd Semester Academic Session: 2023-24 It has a simpler feature set compared to Sass but is still widely used, particularly in environments where simplicity and ease of adoption are priorities. Stylus: Stylus is a CSS preprocessors that emphasizes simplicity and flexibility. It has a minimalist syntax with optional braces and semicolons, allowing for a more concise and expressive coding style. Stylus supports features like variables, nesting, mixins, and functions, similar to Sass and LESS. It is often favored by developers who prefer a more lightweight and customizable tool for CSS pre-processing. Basic Concepts Variables: Variables allow you to store and reuse values throughout your stylesheet. For example, you can define a variable for a color or a font size and use it multiple times throughout your stylesheets. $primary-color: #3498db;.button { background-color: $primary-color; } Nesting: Nesting allows you to nest CSS rules within one another, reflecting the structure of your HTML. This can lead to cleaner and more organized stylesheets. nav { ul { list-style: none; li { Dept. of Computational Sciences 8|Page Brainware University, Kolkata Programme Name: Bachelor of Computer Applications Course Name: HTML,CSS and CSS preprocessors (BCA20002) Class: BCA 2nd Semester Academic Session: 2023-24 display: inline-block; } } } Mixins: Mixins are reusable blocks of styles that can be included within other styles. They enable you to define styles once and reuse them throughout your stylesheet. @mixin flex-center { display: flex; justify-content: center; align-items: center; }.container { @include flex-center; } Functions: Functions allow for advanced manipulation of values within stylesheets. Preprocessors often come with built-in or custom functions for calculations, color manipulation, and more. Dept. of Computational Sciences 9|Page Brainware University, Kolkata Programme Name: Bachelor of Computer Applications Course Name: HTML,CSS and CSS preprocessors (BCA20002) Class: BCA 2nd Semester Academic Session: 2023-24.box { width: percentage(4 / 12); } Partials and Importing: Partials are separate files containing segments of CSS that can be imported into other stylesheets. This promotes modularity and code organization. // _variables.scss $primary-color: #3498db; // main.scss @import 'variables'; Extend/Inheritance: Extend allows you to share a set of CSS properties from one selector to another, promoting code reuse and keeping styles DRY (Don't Repeat Yourself)..button { padding: 10px; border-radius: 5px; }.primary-button { @extend.button; background-color: $primary-color; } Dept. of Computational Sciences 10 | P a g e Brainware University, Kolkata Programme Name: Bachelor of Computer Applications Course Name: HTML,CSS and CSS preprocessors (BCA20002) Class: BCA 2nd Semester Academic Session: 2023-24 Tooling and Workflow Tooling and workflow play a crucial role in the effective use of CSS preprocessors like Sass, LESS, or Stylus. Here's an overview of the tooling and workflow considerations: Installation and Setup: Install the preprocessor compiler globally or locally in your project using npm (Node Package Manager) or another package manager. Set up your project directory structure and configuration files as needed. Text Editors and IDEs: Use text editors or Integrated Development Environments (IDEs) that support syntax highlighting, auto-completion, and integration with preprocessors. Popular choices include Visual Studio Code, Sublime Text, Atom, and JetBrains WebStorm. Build Tools Integration: Integrate preprocessors with build tools like Webpack, Gulp, or Grunt to automate tasks such as compilation, minification, and vendor prefixing. Set up build scripts or configuration files to compile preprocessors code into standard CSS during development or before deployment. Command-Line Compilation: Use command-line interfaces to compile preprocessors code manually or as part of a build process. Familiarize yourself with command-line options and parameters for the preprocessors compiler. Dept. of Computational Sciences 11 | P a g e Brainware University, Kolkata Programme Name: Bachelor of Computer Applications Course Name: HTML,CSS and CSS preprocessors (BCA20002) Class: BCA 2nd Semester Academic Session: 2023-24 Watch Mode: Enable watch mode to automatically recompile preprocessors code whenever changes are detected in the source files. This feature enhances the development workflow by providing real-time feedback and reducing the need for manual compilation. Error Reporting and Debugging: Configure preprocessors to provide detailed error messages and warnings during compilation. Utilize browser developer tools to debug generated CSS code and identify any issues or inconsistencies. Version Control Integration: Include preprocessors source files, configuration files, and compiled CSS output in version control systems like Git. Ensure consistency and collaboration among team members by establishing version control best practices. Linting and Code Quality: Integrate linting tools and code quality checks into your workflow to enforce coding standards, identify potential errors, and maintain code quality. Configure linters to support preprocessors and address any warnings or issues that arise. Optimization and Performance: Implement optimization techniques such as minification, compression, and tree shaking to reduce the size of compiled CSS files and improve performance. Monitor performance metrics and conduct testing to ensure optimal rendering and responsiveness across different devices and browsers. Dept. of Computational Sciences 12 | P a g e Brainware University, Kolkata Programme Name: Bachelor of Computer Applications Course Name: HTML,CSS and CSS preprocessors (BCA20002) Class: BCA 2nd Semester Academic Session: 2023-24 Documentation and Knowledge Sharing: Document your project's tooling and workflow setup to facilitate onboarding for new team members and ensure continuity in development practices. Share knowledge and best practices within your team or community to improve efficiency and collaboration. Integrating preprocessors with build tools (e.g., Webpack, Gulp) Integrating CSS preprocessors like Sass, LESS, or Stylus with build tools such as Webpack or Gulp can significantly enhance your development workflow. Here's how you can integrate preprocessors with these build tools: 1. Webpack Integration: Step 1: Install Necessary Packages: Install the required webpack loaders for processing CSS preprocessors. For Sass, you would typically need sass-loader and node-sass. Step 2: Configure Webpack: Add rules in your webpack configuration file to handle preprocessors. This includes specifying the loader for the preprocessors files and any additional options. Example Webpack Configuration: JavaScript Copy code Dept. of Computational Sciences 13 | P a g e Brainware University, Kolkata Programme Name: Bachelor of Computer Applications Course Name: HTML,CSS and CSS preprocessors (BCA20002) Class: BCA 2nd Semester Academic Session: 2023-24 module. Exports = { // Other webpack config options... module: { rules: [ { test: /\. sass$/, // Adjust pattern for other preprocessors use: [ 'Style-loader', // Adds CSS to the DOM by injecting a tag 'CSS-loader', // Translates CSS into CommonJS modules 'Sass-loader' // Compiles Sass to CSS ] } ] } }; Step 3: Run Webpack: Run webpack in your project directory. It will compile your preprocessors files into CSS during the build process. 2. Gulp Integration: Step 1: Install Necessary Packages: Install Gulp and Gulp plugins required for processing CSS preprocessors. For example, you would need gulp-sass for Sass compilation. Step 2: Configure Gulp Tasks: Dept. of Computational Sciences 14 | P a g e Brainware University, Kolkata Programme Name: Bachelor of Computer Applications Course Name: HTML,CSS and CSS preprocessors (BCA20002) Class: BCA 2nd Semester Academic Session: 2023-24 Define Gulp tasks to handle pre-processing. This typically involves specifying source files, destination directories, and applying relevant Gulp plugins. Example Gulp Configuration: const gulp = require('gulp'); const sass = require('gulp-sass'); function compileSass() { return gulp.src('src/scss*.scss').pipe(sass().on('error', sass.logError)).pipe(gulp.dest('dist/css')); } exports.default = gulp.series(compileSass); Step 3: Run Gulp Tasks: Run Gulp tasks in your terminal. For the example above, you would run gulp or gulp default to compile Sass files into CSS. Benefits of Integration: Automates the compilation process, saving time and effort. Enables seamless integration of preprocessors into your build pipeline. Supports other build processes like minification, auto prefixing, and bundling alongside pre-processing. Dept. of Computational Sciences 15 | P a g e Brainware University, Kolkata Programme Name: Bachelor of Computer Applications Course Name: HTML,CSS and CSS preprocessors (BCA20002) Class: BCA 2nd Semester Academic Session: 2023-24 Using command-line compilers Using command-line compilers for CSS preprocessors like Sass, LESS, or Stylus allows for efficient compilation of preprocessors code into standard CSS. Here's how you can use command-line compilers for each of these preprocessors: 1. Sass: Step 1: Install Sass: If Sass is not already installed on your system, you can install it globally using npm (Node Package Manager) with the following command: npm install -g sass Step 2: Compile Sass Files: Navigate to your project directory containing Sass files (*.scss) in the command-line interface. Use the sass command followed by the source Sass file and the destination CSS file: sass input. CSS output.css Example: sass styles. CSS styles.css Dept. of Computational Sciences 16 | P a g e Brainware University, Kolkata Programme Name: Bachelor of Computer Applications Course Name: HTML,CSS and CSS preprocessors (BCA20002) Class: BCA 2nd Semester Academic Session: 2023-24 2. LESS: Step 1: Install LESS: If LESS is not already installed on your system, you can install it globally using npm with the following command: npm install -g less Step 2: Compile LESS Files: Navigate to your project directory containing LESS files (*. less) in the command-line interface. Use the lessc command followed by the source LESS file and the destination CSS file: lessc input.less output.css Example: lessc styles.less styles.css 3. Stylus: Step 1: Install Stylus: If Stylus is not already installed on your system, you can install it globally using npm with the following command: npm install -g stylus Step 2: Compile Stylus Files: Navigate to your project directory containing Stylus files (*.styl) in the command-line interface. Dept. of Computational Sciences 17 | P a g e Brainware University, Kolkata Programme Name: Bachelor of Computer Applications Course Name: HTML,CSS and CSS preprocessors (BCA20002) Class: BCA 2nd Semester Academic Session: 2023-24 Use the stylus command followed by the source Stylus file and the destination CSS file: stylus input.styl -o output.css Example: stylus styles.styl -o styles.css Benefits of Using Command-Line Compilers: Flexibility: Command-line compilers can be easily integrated into various development workflows and build processes. Efficiency: Allows for quick compilation of preprocessor code without the need for a graphical user interface. Automation: Can be automated using scripts or build tools for continuous integration and deployment pipelines. Portability: Command-line compilers work across different operating systems, making them suitable for teams with diverse development environments. Dept. of Computational Sciences 18 | P a g e Brainware University, Kolkata