Some Things You Should Know When Working With Units

From the Author: Webpack is a JavaScript module bundler that transforms web resources such as HTML, CSS, JavaScript, and SVG files and bundles them into a smaller group of files.  Webpack also helps with chunking (splitting into smaller chunks) and managing code dependencies to ensure that the code that needs to be loaded first does this.  How webpack works In this article, we'll go over some of the new features to look out for in webpack in 2021, but first we'll look at what's new in webpack in 2020.  webpack V4 - V5: Important Changes In October 2020, a newer version of webpack was released: webpack 5. This version removes all deprecated elements in V4 and fixes critical bugs to bring the webpack architecture up to par for future improvements.  JavaScript.  Quick Start Learn the basics of JavaScript with a hands-on example of building a web application Learn more Other interesting features in version 5: Long-Term Caching Support - New algorithms to support long-term caching are enabled by default in production mode.  The real hash of the content - previously only the hash of the internal structure was used in webpack.  Webpack 5 will use the real hash of the file content when used [contenthash], which will have a positive effect on long-term caching when only small changes are made to the file.  Modular structure - webpack 5 came with a new feature that allows multiple webpack builds to work together.  See here for the complete changelog.  While 2020 has been a big year for webpack, there is still a lot more to come, which we'll talk about in the following sections.  Please note that these updates are subject to change based on the ever-changing world of web developers.  Webpack roadmap 2021 Improved ESM support Since the ECMAScript Module (ESM) was introduced in 2015, it has become the standard mechanism for code reuse in highly fragmented JavaScript applications.  To improve ESM support, the webpack team is planning to make some important updates.  Self-executing snippets One of the most interesting features of webpack is code splitting.  This feature allows you to split your code into multiple packages that you can download on demand or in parallel.  At the moment, dynamically loaded fragments in webpack usually serve as a container for modules and never execute module code directly.  For example, writing: JavaScript import ("./ module") 1 import ("./ module") Will compile like this: JavaScript __webpack_load_chunk __ ("chunk-containing-module.js"). Then (() => __webpack_require __ (" ./module ")) 1 __webpack_load_chunk __ (" chunk-containing-module.js "). then (() => __webpack_require __ (" ./ module ")) In most cases this cannot be changed, but the webpack command considers some cases where webpack could generate a block that directly executes the contained module.  This can result in less code generated.  ESM imports and exports While there is already a plugin for generating ESM exports, the webpack team is considering adding built-in support for this feature, which may be useful when you decide to integrate webpack packages into ESM boot environments or inline scripts.  JavaScript.  Quick Start Learn the basics of JavaScript with a hands-on example of building a web application Learn More The command also takes absolute URLs into account when importing.  This is very useful when using external services that offer their APIs as EcmaScript modules.  Here's an example: JavaScript import {event} from "https://analytics.company.com/api/v1.js" // Changes to: import ("https://analytics.company.com/api/v1.js" ) 12345 import {event} from "https://analytics.company.com/api/v1.js" // Changes to: import ("https://analytics.company.com/api/v1.js") Such the function will help to gracefully handle errors with external dependencies.  ESM Library The webpack team will also try to improve the bundling using the ESM libraries and will add a special mode that does not apply chunking, but instead generates rendered modules that can be plugged in via ESM imports and exports.  This means that as long as loaders, graphics modules, and resource optimizers are running, no fragment graphs will be created.  Instead, each module in the modules graph will be released as a separate file.  Strict Mode Caveats Sooner or later, the webpack team plans to ensure that all contained code is put into strict mode when the ESM package is created.  While this may not be a problem for many modules, there are a few older packages that may have problems with different interpretations, so it would be nice to see warnings for them.  SourceMap Performance SourceMap provides a way to map code in a compressed file back to its original position in the original file.  In other words, it links the minified version of the resource (CSS or JavaScript) to the original authoring version.  This utility helps you debug applications even after resources have been compressed / optimized.  Using SourceMap in webpack is currently quite expensive due to performance issues, so the webpack team will be looking to improve this in 2021.  They will also be looking to update / improve the terser plugin, which is the default webpack minifier in webpack 5. Package.json export / import field Node.js v14 came with support for an export field in package.json.  This feature allows you to directly define entry points for a package, or conditionally define entry points for each environment or JavaScript flavor (TypeScript, Elm, CoffeeScript, etc.).  In a later release, private imports were also supported in Node.js (similar to the export field in package.json).  For now, webpack 5 only supports the export function, even with additional conditions such as specifying production / development.  Import fields for private imports are another feature to look out for in 2021.  HMR for Modular Design Hot Module Replacement (HMR) works by replacing, adding, or removing modules while the application is still running, without the need for a complete reboot.  This can significantly speed up development by preserving application state that would have been lost on a hard reboot.  Plus, it instantly refreshes the page when changes are made to the source code, much like changing styles directly in the browser developer tools.  Webpack 5 ships with a new feature called “Module Federation”.  This feature allows you to integrate multiple assemblies together at runtime.  HMR currently only supports one assembly at a time and updates cannot move between assemblies.  The webpack team will work to improve the HMR updates to move between different builds, making it easier to develop federation apps.  Hint System To monitor errors and warnings, the webpack team is considering adding another category for the user: hint.  Similar to displaying errors and warnings, a tooltip notifies the user of information that may be of value to him.  However, unlike the previous categories, the prompt will identify optimization opportunities or tricks, not problems.  An example hint might look something like: "Did you know that when you add X a change to file Y, you can clean it up?";  or "Easy to encode the space with the space function."  WebAssembly According to the official documentation, WebAssembly (abbreviated Wasm) is "a binary instruction format for a stack-based virtual machine."  This means that you can build your software with programming languages ​​like Rust, C ++ and Python and provide it to the end user in a browser with near-native performance.  In the current version of webpack, WebAssembly is experimental and not enabled by default.  The default support is what the webpack team will hopefully add this year.  Conclusion There are big changes coming to webpack in 2021, and while this list may not be final, we can look forward to new features and capabilities that will make webpack easier and more efficient.  Author: Elijah Asaolu Source: blog.logrocket.com Editorial: The webformyself team.  JavaScript.  Quick Start Learn the basics of JavaScript with a hands-on example of building a web application Learn More Webpack.  The Basics Watch the Webpack Video!  Look

From the author: David Cheinin wrote a generic article summarizing the problem of setting the height of an element to 100vh in mobile browsers and then placing something at the bottom.

Take a look at the image below:

The problem is that Chrome ignores the address bar when it determines how to shrink an element, which causes the bottom of the element to actually be outside the bottom edge of the viewport.

JavaScript. Fast start

Learn JavaScript basics with a hands-on example of building a web application

Learn more

You can expect this button in the image to be visible (assuming the element is at the top of the page and you haven’t scrolled it) because it sits along the bottom edge of the 100vh element. But it is actually hidden in mobile browsers, including iOS Safari or Android Chrome.

I use this a lot:

This is just a quick way to ensure that the body expands to its full height, without any other elements. I usually do this in simple demos, but I am told that even this is a bit problematic because you might get nervous when the address bar appears and disappears, or things might not be centered as you expected.

JavaScript. Fast start

Learn JavaScript basics with a hands-on example of building a web application

Learn more

You might think body {height: 100%} would solve the problem, but there are pitfalls here as well. body is a descendant of html and has the same height as its content as any other element.

If you need the body to take up the entire height, you also need to deal with the HTML element:

… which is not that difficult.

It is difficult to arrange things along the bottom edge. This is problematic because of the container position: absolute; inside “full height” (which is often above the viewport).

If you try to place something like a fixed navigation bar at the bottom of the screen, you probably do it with position: fixed; bottom: 0; and that seems to work fine. The address bar will push this down, as you would expect.

Viewport-based horizontal units are just as weird and problematic because of another element of the browser UI: scrollbars. If there is a visible scrollbar in the browser window, that scrollbar usually fits into visual space, although the value of 100vw is calculated as if the scrollbar were not there. In other words, 100vw will result in a horizontal scrollbar, which you probably don’t expect.

In our last roundup of CSS wishlists, improved viewport-based unit handling was mentioned several times, so the developers are clearly interested in having better solutions for these things. I’m not sure what this will mean for web compatibility, because changing the way they work might break all the workarounds we’ve used before and which certainly still work in our projects.

Author: Chris coyier

A source: //css-tricks.com

Editorial staff: Webformyself team.

JavaScript. Fast start

Learn JavaScript basics with a hands-on example of building a web application

Learn more

CSS3. The basics

Learn CSS3 from scratch right now!

Look

Leave a Reply

Your email address will not be published. Required fields are marked *