Add custom blocks questions and answers

Author: sudheerj

README.md

@@ -135,6 +135,9 @@ List of 300 VueJS Interview Questions
 |126| [How do you apply linting for css?](#how-do-you-apply-linting-for-css)|
 |127| [How do you use eslint plugin?](#how-do-you-use-eslint-plugin)|
 |128| [What is the purpose of eslint loader?](#what-is-the-purpose-of-eslint-loader)|
+|129| [What is CSS extraction?](#what-is-css-extraction)|
+|130| [What are custom blocks?](#what-are-custom-blocks)|
+|131| [What are the features of stylelint?](#what-are-the-features-of-stylelint?)|
 
 1. ### What is VueJS?
  **Vue.js** is an open-source, progressive Javascript framework for building user interfaces that aim to be incrementally adoptable. The core library of VueJS is focused on the `view layer` only, and is easy to pick up and integrate with other libraries or existing projects.
@@ -2371,4 +2374,59 @@ List of 300 VueJS Interview Questions
  ]
  }
  }
- ```
+ ```
+129. ### What is CSS extraction?
+ CSS Extraction is used to extract all the processed CSS in all Vue components into a single CSS file. For webpack4, you need to install below npm command,
+ ```javascript
+ npm install -D mini-css-extract-plugin
+ ```
+ You can configure this plugin in webpack as below,
+ ```javascript
+ // webpack.config.js
+ var MiniCssExtractPlugin = require('mini-css-extract-plugin')
+
+ module.exports = {
+ // other options...
+ module: {
+ rules: [
+ // ... other rules omitted
+ {
+ test: /\.css$/,
+ use: [
+ process.env.NODE_ENV !== 'production'
+ ? 'vue-style-loader'
+ : MiniCssExtractPlugin.loader,
+ 'css-loader'
+ ]
+ }
+ ]
+ },
+ plugins: [
+ // ... Vue Loader plugin omitted
+ new MiniCssExtractPlugin({
+ filename: 'style.css'
+ })
+ ]
+ }
+ ```
+130. ### What are custom blocks?
+ You can define custom language blocks inside *.vue files based on the `lang` attribute of the block, the block's tag name, and the rules in your webpack config. You can also use `resourceQuery` to match a rule against a custom block with no lang. For example, to match against <message> custom blocks.
+ ```javascript
+ {
+ module: {
+ rules: [
+ {
+ resourceQuery: /blockType=message/,
+ loader: 'loader-to-use'
+ }
+ ]
+ }
+ }
+ ```
+131. ### What are the features of stylelint?
+ Below are the list of major stylelint features
+ 1. It has more than **160 built-in rules** to catch errors, apply limits and enforce stylistic conventions
+ 2. Understands **latest CSS syntax** including custom properties and level 4 selectors
+ 3. It **extracts embedded styles** from HTML, markdown and CSS-in-JS object & template literals
+ 4. Parses **CSS-like syntaxes** like SCSS, Sass, Less and SugarSS
+ 5. Supports **Plugins** for reusing community plugins and creating own plugins