| # minify-html-literals |
| |
| _Minify HTML markup inside JavaScript template literal strings._ |
| |
| [](https://www.npmjs.com/package/minify-html-literals) |
| [](https://travis-ci.com/asyncLiz/minify-html-literals) |
| [](https://coveralls.io/github/asyncLiz/minify-html-literals?branch=master) |
| |
| ## Why? |
| |
| Template literals are often used in JavaScript to write HTML and CSS markup (ex. [lit-html](https://www.npmjs.com/package/lit-html)). This library allows a developer to minify markup that is normally ignored by JavaScript minifiers. |
| |
| ## Usage |
| |
| ```js |
| import { minifyHTMLLiterals } from 'minify-html-literals'; |
| // const minifyHTMLLiterals = require('minify-html-literals').minifyHTMLLiterals |
| |
| const result = minifyHTMLLiterals( |
| `function render(title, items) { |
| return html\` |
| <style> |
| .heading { |
| color: blue; |
| } |
| </style> |
| <h1 class="heading">\${title}</h1> |
| <ul> |
| \${items.map(item => { |
| return getHTML()\` |
| <li>\${item}</li> |
| \`; |
| })} |
| </ul> |
| \`; |
| }`, |
| { |
| fileName: 'render.js' |
| } |
| ); |
| |
| console.log(result.code); |
| // function render(title, items) { |
| // return html`<style>.heading{color:#00f}</style><h1 class=heading>${title}</h1><ul>${items.map(item => { |
| // return getHTML()`<li>${item}</li>`; |
| // })}</ul>`; |
| // } |
| |
| console.log(result.map); |
| // { |
| // "version": 3, |
| // "file": "render.js.map", |
| // "sources": ["render.js"], |
| // "sourcesContent": [null], |
| // "names": [], |
| // "mappings": "AAAA;gBACgB,qDAMU,QAAQ,SAE1B;2BACmB,IACX,OAAO,KACb;WACC,KAEP;" |
| // } |
| ``` |
| |
| ### ES5 Transpiling Warning |
| |
| Be sure to minify template literals _before_ transpiling to ES5. Otherwise, the API will not be able to find any template literal (`` `${}` ``) strings. |
| |
| ## Supported Source Syntax |
| |
| - JavaScript |
| - TypeScript |
| |
| ## Options |
| |
| ### Basic |
| |
| The following options are common to typical use cases. |
| |
| | Property | Type | Default | Description | |
| | --------------------------- | -------------------------------------------------------------------------------------------- | ------------------------- | ------------------------------------------------------------------------------------------------------------------------------------------------------------------------- | |
| | `fileName` | string | | _Required._ The name of the file, used for syntax parsing and source maps. | |
| | `minifyOptions?` | [html-minifier options](https://www.npmjs.com/package/html-minifier#options-quick-reference) | `defaultMinifyOptions` | Defaults to production-ready minification. | |
| | `minifyOptions?.minifyCSS?` | [clean-css options](https://www.npmjs.com/package/clean-css#constructor-options) | `defaultMinifyCSSOptions` | Uses clean-css defaults. | |
| | `shouldMinify?` | function | `defaultShouldMinify` | A function that determines whether or not an HTML template should be minified. Defaults to minify all tagged templates whose tag name contains "html" (case insensitive). | |
| | `shouldMinifyCSS?` | function | `defaultShouldMinifyCSS` | A function that determines whether or not a CSS template should be minified. Defaults to minify all tagged templates whose tag name contains "css" (case insensitive). | |
| |
| ### Advanced |
| |
| All aspects of the API are exposed and customizable. The following options will not typically be used unless you need to change how a certain aspect of the API handles a use case. |
| |
| | Property | Type | Default | Description | |
| | ----------------------- | ------------------------------------------------------------------------- | -------------------------------------------------------------- | ---------------------------------------------------------------------------------------------------------------------------------------------------------- | |
| | `generateSourceMap?` | boolean or `(ms: MagicString, fileName: string) => SourceMap | undefined` | `defaultGenerateSourceMap` | Set to `false` to disable source maps, or a custom function to control how source maps are generated from a `MagicString` instance. | |
| | `strategy?` | object | `defaultStrategy` | An object with methods defining how to minify HTML. The default strategy uses [html-minifier](https://www.npmjs.com/package/html-minifier). | |
| | `validate?` | boolean or object | `defaultValidation` | Set to `false` to disable strategy validation checks, or to a custom set of validation functions. This is only useful when implementing a custom strategy. | |
| | `parseLiterals?` | function | [parse-literals](https://www.npmjs.com/package/parse-literals) | Override the function used to parse template literals from a source string. | |
| | `parseLiteralsOptions?` | object | | Additional options to pass to `parseLiterals()` | |
| | `MagicString?` | function | [MagicString](https://www.npmjs.com/package/magic-string) | Override the MagicString-like constructor to use for manipulating the source string and generating source maps. | |
| |
| ## Customization Examples |
| |
| ### Minify non-tagged templates |
| |
| > This is particularly useful for libraries that define templates without using tags, such as Polymer's `<dom-module>`. |
| |
| ```js |
| import { minifyHTMLLiterals, defaultShouldMinify } from 'minify-html-literals'; |
| |
| minifyHTMLLiterals( |
| ` |
| template.innerHTML = \` |
| <dom-module id="custom-styles"> |
| <style> |
| html { |
| --custom-color: blue; |
| } |
| </style> |
| </dom-module> |
| \`; |
| `, |
| { |
| fileName: 'render.js', |
| shouldMinify(template) { |
| return ( |
| defaultShouldMinify(template) || |
| template.parts.some(part => { |
| return part.text.includes('<dom-module>'); |
| }) |
| ); |
| } |
| } |
| ); |
| ``` |
| |
| ### Do not minify CSS |
| |
| ```js |
| import { minifyHTMLLiterals, defaultMinifyOptions } from 'minify-html-literals'; |
| |
| minifyHTMLLiterals(source, { |
| fileName: 'render.js', |
| minifyOptions: { |
| ...defaultMinifyOptions, |
| minifyCSS: false |
| }, |
| shouldMinifyCSS: () => false |
| }); |
| ``` |
| |
| ### Modify generated SourceMap |
| |
| ```js |
| minifyHTMLLiterals(source, { |
| fileName: 'render.js', |
| generateSourceMap(ms, fileName) { |
| return ms.generateMap({ |
| file: `${fileName}-converted.map`, // change file name |
| source: fileName, |
| includeContent: true // include source contents |
| }); |
| } |
| }); |
| ``` |