webpack dynamic import not working webpack dynamic import not working

anytime.bundle.js 109 KiB 0 [emitted] anytime // In this example, the page shows an `input` tag and a button. webpackPreload: Tells the browser that the resource might be needed during the current navigation. Why are Suriname, Belize, and Guinea-Bissau classified as "Small Island Developing States"? However, if you try with any other module than cat, the same error will appear: This feature could be used to enforce modules to be loaded beforehand, so that you ensure that at a certain point the modules accessible. ? Actually webpack would enforce the recommendation for .mjs files, .cjs files or .js files when their nearest parent package.json file contains a "type" field with a value of either "module" or "commonjs". If Magic Comments (or Any Comment) are not reaching the webpack, then they are lost in the transpiling process. https://github.com/roblan/webpack-external-promise-import, __webpack_require__ should not be called on promise external result. Have a question about this project? Webpack: Common chunks for code shared between Webworker and Web code? hey @sowinski, because that's an external script, you can't import it and access its contents directly. Let's learn how to enable HTTPS on localhost for a PHP application on Apache by Dockerizing it. With this, it's also close to the lazy mode, as far as the lazy chunk goes. Site design / logo 2023 Stack Exchange Inc; user contributions licensed under CC BY-SA. Let's first see the example which we'll use throughout this section: As you can see, the mode can be specified with the webpackMode: 'eager' magic comment. Asking for help, clarification, or responding to other answers. Where does this (supposedly) Gibson quote come from? React Lazy This React component is a function that takes another function as an argument. What is the expected behavior? // variable will be executed and retrieved. By clicking it, the chunk will be fetched and the cat module will become accessible and that is because when a chunk is loaded, all of its modules will become available for the entire application. Note that webpack ignores the name argument. It's able to require modules without indicating they should be bundled into a chunk. Here it would return { default: 42 }, You are right - my expected behavior part is wrong, but either way it does not work (it works fine with static imports though, so it'a bit inconsistent? In this case, having only a responsive design doesnt cover what you want, so you build a page renderer which loads and renders the page based on the user platform. Find centralized, trusted content and collaborate around the technologies you use most. When using the eager mode, there won't be any additional chunks created. Thanks for contributing an answer to Stack Overflow! Is it suspicious or odd to stand by the gate of a GA airport watching the planes? In this situation, the cat.js file is a CommonJS module and the rest are ES modules: The StackBlitz app for this new example can be found here. Dynamic Import from external URL will throw, v2 Addon Format (Embroider compatibility), Dynamic Import not working with variable path. you are just linking to stuff outdated links. Note that setting webpackIgnore to true opts out of code splitting. Pablo Montenegro 38 Followers https://pablo.gg Follow More from Medium Gejiufelix in The keyword here is statically. This is because webpack can't know during the compilation what modules will be imported. Refresh the page, check Medium 's site status, or find something interesting to read. you can get around this by using that attribute as the src attribute in a script tag. We will start with a straightforward example which will initially throw an error and then we will expand on it in order to get a better understanding of what this weak mode is about: A StackBlitz app with the example can be found here(make sure to run npm run build and npm run start to start the server). It's also worth exploring a case where the array has the module's exports type specified. webpackChunkName not effective and working with Babel? You signed in with another tab or window. Euler: A baby on his lap, a cat on his back thats how he wrote his immortal works (origin? import('http://example.com/some-module/some-module.bundle.js').then(module => console.log(module.default)); How can I load an external resource from an external url? fish.js Webpack adds a really nice feature to the dynamic imports, the magic comments. Adding the following webpack config with extensionAlias to the next.config.js file (see Workaround 1 in this other issue): /** @type {import("next").NextConfig} . However, it does not necessarily guarantee that the cat module is available. Entrypoint anytime = anytime.css anytime.bundle.js cisco gateway of last resort is not set. webpackIgnore: Disables dynamic import parsing when set to true. Using fetch I could load the images dynamically from the public folder and start webpack without getting ever again a memory issue. Unfortunately I found it's more complex than I expected to fix it, I'm going to close my pull request so anyone interested in it can continue. Styling contours by colour and by line thickness in QGIS. Bundling can be limited to a specific directory or set of files so that when you are using a dynamic expression - every module that could potentially be requested on an import() call is included. However, this support does not work with dynamic import() Workaround. Although it worked with webpack@3. To see an example of what that array would look like, you can open the StackBlitz app whose link can be found at the beginning of this section(or here) and run the npm run build script. How can I check before my flight that the cloud separation requirements in VFR flight rules are met? If you type cat in the input and then press the button, you'll notice an error in the console: And this should make sense because, as it's been mentioned previously, the weak import expects that the resource should already be ready to be used, not to make webpack take action in order to make it available. Can you write oxidation states with negative Roman numerals? This is the lazy option's behaviour. Moreover, all the modules that this newly loaded chunk contains will be registered by webpack. [5] ./sources/views/admin/win_add_subsuser.js 3.19 KiB {0} [built] /* webpackChunkName: 'animal', webpackMode: 'eager' */, /* Now here's the part that errors on build. By clicking Accept all cookies, you agree Stack Exchange can store cookies on your device and disclose information in accordance with our Cookie Policy. I needed 'babel-plugin-syntax-dynamic-import' in my .babelrc file. Inline comments to make features work. Ive tried several different variations of the imports. Adding asssets outside of the module system. The tools that provide this kind of features are: RequireJS, SystemJS, Webpack, Rollup and curl. The First line of the Readme of the repo: And this is what is causing all the trouble. More specifically, considering the same file structure. Does anyone yet has found a solution? By clicking Accept all cookies, you agree Stack Exchange can store cookies on your device and disclose information in accordance with our Cookie Policy. NOTE: This plugin is included in @babel/preset-env, in ES2020. Can you write oxidation states with negative Roman numerals? The callback will be called with the exports of each dependency in the dependencies array. Well occasionally send you account related emails. While webpack supports multiple module syntaxes, we recommend following a single syntax for consistency and to avoid odd behaviors/bugs. They are capable of bundling your app and generating your bundle chunks, and especially lazy loading them, so you can load only the one that you need at a given time. The traversal starts from the first static part of the provided path(in this case it is ./animals) and in each step it will read the files from the current directory and will test the RegExp object against them. This looks like an obvious problem and with that many libraries out there, someone must have found a solution I guess. to your account, I made a vue component package my-custom-comp, which contains dynamic import: Multiple requires of the same module result in only one module execution and only one export. Thereby I am using webpacks dynamic import syntax like so import('../images_svg/' + svgData.path + '.svg') sadly this doesn't work. to get it working. As prefetch makes the chunk be loaded on the idle time, you can add numbers as the parameter to say to Webpack what is the priority of each one: The bar.js module has a higher priority to load, so it will be prefetched before foo.jpg and slowpoke.js will be the last one(priority -100). Flask api hosted as a docker container works with localhost:5000 but not with 172.17..2:5000; Python Flask heroku application error; Failed to compute cache key: "/films" not found: not found? Would anyone have any ideas as to why webpack wouldnt create the chunk files? The following options are supported: webpackPrefetch: Tells the browser that the resource is probably needed for some navigation in the future. What is the !! animals Have a question about this project? By using weak imports, we're essentially telling webpack that the resources we want to use should already be prepared for retrieval. Angular implements two strategies to control change detection behavior on the level of individual components. In other words, it keeps track of modules' existence. The result of the dynamic import is an object with all the exports of the module. @sokra Could you be more specific? Since webpack 2.6.0, the placeholders [index] and [request] are supported within the given string to an incremented number or the actual resolved filename respectively. They will just be placed into an object/array of modules and when the button it clicked, it will execute and retrieve that module on the spot, without additional network requests or any other asynchronous operations. Do new devs get fired if they can't solve a certain bug? CommonJS or AMD modules cannot be consumed. The text was updated successfully, but these errors were encountered: You could use webpackIgnore comment if you want to use import to load an external file: This directive comment prevents webpack from parsing the import expression. [0] ./node_modules/webix-jet/dist/index.js + 17 modules 48.3 KiB {0} [built] Inline Including hashes related to the file contents to their names allows to invalidate them on the client-side. Using Kolmogorov complexity to measure difficulty of problems? Created and exported a composite function to do the work, which is able to load for any platform we want using expressions, plus we already exposed two loaders, one for desktop and other for mobile. If I want to use the cat module, after clicking on the button, I should see a new request for the chunk which contains the module in question: As probably noticed, the console tells us that the chunk has been loaded, as well as the module it contains, namely the cat module. And consider adding service workers with a good caching strategy. Although the value is not known at compile time, by using the import() function with dynamic arguments we can still achieve lazy loading. What am I doing wrong? A prefetched chunk is downloaded in browser idle time. It is recommended to treat it as an opaque value which can only be used with require.cache[id] or __webpack_require__(id) (best to avoid such usage). A normal import statement cannot be used dynamically within other logic or contain variables. We hand-pick interesting articles related to front-end development. // Here the user chooses the name of the file. It's important to mention that the traversal and the file discovery are done at compile time. That's because the chunk will be served from a cache internally maintained by webpack and the required module will be retrieved from the array/object of modules where webpack records them. [37] ./sources/anytime.js 2.12 KiB {0} [built] Theoretically Correct vs Practical Notation, How do you get out of a corner when plotting yourself into a corner, How to handle a hobby that makes income in US, Replacing broken pins/legs on a DIP IC package, Surly Straggler vs. other types of steel frames. [41] ./sources/locales sync ^\.\/.$ 181 bytes {0} [built] But I'm not being able to dynamically load external libraries from variables. Note that all options can be combined like so /* webpackMode: "lazy-once", webpackChunkName: "all-i18n-data" */. Based on the default configuration, our initial expression ./animals/${fileName}.js will result in ./animals/. Dynamic import seems to be the solution but Im not having any luck getting webpack to create the chunk files. Old solution A solution is to use node --max_old_space_size=8000 scripts/start.js to get it working. Dynamically load modules. Keep in mind that you will still probably need babel for other ES6+ features. The file loader will basically map the emitted file path inside a module. Javascript is not recognizing a Flask variable; Jinja2 - Expressions concatenating issue; Recursion with WTForms and Jinja The way webpack handles this behavior internally is by having a map where the keys are the filenames(in this case, the keys are the filenames from the animals directory) and the values are arrays(as we will see, the array's pattern will be{ filename: [moduleId, chunkId] }). In this article we've learned that the import function can do much more than simply creating a chunk. Well, practically it isn't, because all those possible chunks are just files held on the server which are not sent to the browser unless the browser requires them(e.g when the import()'s path matches an existing file path). Using Webpack and the dynamic import structure it creates a promise that will retrieve the chunk at runtime and allow you to act on it at that point. @sokra @evilebottnawi Any updates on this issue? If this function returns a value, this value is exported by the module. - A preloaded chunk should be instantly requested by the parent chunk. This issue had no activity for at least three months. just load them when used. I don't know if there's a cleaner way, but I've seen script.js used with success for the google maps api specifically. This will result in the following output: Without require.include('a') it would be duplicated in both anonymous chunks. Node.js version: 10.3.0 Here's the function which calls the dynamic import: Everything I have read says this is the way to set this up. The dependency must export values with the export label. For instance: In the above map(which can be found in the dist/main.js file - the only generated file), it is known for sure that the cat module is used across the app. Lazy Loading is a hot topic for the optimization of web applications. Therefore a cache in the runtime exists. Are the Webpack Magic Comments Node.js version: v14.4.0 Does a summoned creature play immediately after being summoned by a ready action? // Requesting the module that should already be available. Dynamic imports stopped working in Webpack v4. 7 indicates a CommonJS module and in this case webpack needs to create a fake ES module from it.To see it in practice, you can open the last provided example and start the server. You do not need to add curly brackets. This implies that the resources in question should by now be loaded(i.e required and used) from somewhere else, so as to when a weak import is used, this action doesn't trigger any fetching mechanisms(e.g making a network request in order to load a chunk), but only uses the module from the data structure that webpack uses to keep track of modules. Although it is a popular selling point of webpack, the import function has many hidden details and features that many developers may not be aware of. Not the answer you're looking for? [8] ./sources/views/timeclock/win_userdepts.js 3.39 KiB {0} [built] webpack generated code (added line breaks for clarity): part .then((m) => __webpack_require__.t(m, 7)) seems to be unnecessary. require.ensure([], function(request) { request('someModule'); }) isn't handled by webpack's static parser. Recovering from a blunder I made while emailing a professor. Keep in mind that you will still probably need babel for other ES6+ features. The other modules whose values are null are called orphan modules. It's subject to automatic issue closing if there is no activity in the next 15 days. Sign up for a free GitHub account to open an issue and contact its maintainers and the community. It's because I am using the presets in Babel; comments are on by default. Ok, I do this for a lot of images, this turned into a big problem and because of this extra requests, the images are slower to load. If you use require.ensure with older browsers, remember to shim Promise using a polyfill such as es6-promise or promise-polyfill. privacy statement. - A preloaded chunk has medium priority and instantly downloaded. Aside from the module syntaxes described above, webpack also allows a few custom, webpack-specific methods: Specify a whole group of dependencies using a path to the directory, an option to includeSubdirs, a filter for more fine grained control of the modules included, and a mode to define the way how loading will work. // Here the user chooses the name of the module. Any module that matches will not be bundled. Using fetch I could load the images dynamically from the public folder and start webpack without getting ever again a memory issue. The require label can occur before a string. Although the articles use React and React+Redux on the examples, you can apply the same very idea in any SPA based framework/library: Code splitting is a powerful thing to make your application faster, smartly loading the dependencies on the run. Let's take a deep dive into docker volume & its configuration options. eg: ./locale. *.js(loosely).In the upcoming sections we will explore what happens once these files have been figured. It is crucial to have a (root) parent chunk because it contains the required logic to fetch and integrate other child chunks in the application. webpackChunkName: A name for the new chunk. Refresh the page, check. Meaning, this code can be run within execution, only loading the dependencies if certain conditions are met. Thus, there are 3 filters that a module must overcome: it must match with the imports expression, it must be used across the app(e.g it is directly imported or imported through a chunk) and it must be available(i.e already loaded from somewhere else). I am trying to implement the same hook in Preact + Vite: dynamic . Moving the files I wanted to import outside of the views folder worked. To subscribe to this RSS feed, copy and paste this URL into your RSS reader. See this thread to the problem https://github.com/webpack/webpack/issues/5747. The following AMD methods are supported by webpack: If dependencies are provided, factoryMethod will be called with the exports of each dependency (in the same order). There is also an article named An in-depth perspective on webpack's bundling process in which concepts such as Modules and Chunks are explained, but it shouldn't affect the understanding of this article too much. Refresh the page, check Medium 's site status, or find something interesting to read. - Coco Jun 21, 2018 at 20:36 Already have this plugin installed, and it still does not work. You may want to look into output.publicPath to setup to correct URL. Basically, this technique ensures that certain modules are only loaded when they are required by the users. *$/, any file */, /* optional, 'sync' | 'eager' | 'weak' | 'lazy' | 'lazy-once', default 'sync' */. What happens in this example is that the user will type the name of an animal into the input and when the button is clicked, the chunk which corresponds to that name will be loaded. Here's my test repository https://github.com/younabobo/webpack-dynamic-import-test, @younabobo @evilebottnawi If the current behavior is a bug, please provide the steps to reproduce. Adding this comment will cause our separate chunk to be named [my-chunk-name].js instead of [id].js. Calls to import() are treated as split points, meaning the requested module and its children are split out into a separate chunk. However, according to MDN and Google Developer Website, dynamic import should support loading scripts from remote source. If you run npm run build and check the dist/main.js file, the map will look a bit different: Here, the pattern is this: { filename: [moduleId, moduleExportsMode, chunkId] }. You can think of a dynamic expression as anything that's not a raw string(e.g import('./path/to/file.js')). Browse other questions tagged, Where developers & technologists share private knowledge with coworkers, Reach developers & technologists worldwide, Using a library like axios and putting the SVGs in the public folder is a solution but I think it's really not the recommended way, the link ( Adding asssets outside of the module system ) doesn't lead to the explanation anymore :<. You put it in like so: "syntax-dynamic-import". You put it in like so: "syntax-dynamic-import". True, even if were dynamic loading the components, this stills a pretty attached solution. A few examples of dynamic expressions could be: import('./animals/' + 'cat' + '.js'), import('./animals/' + animalName + '.js'), where animalName could be known at runtime or compile time. The diagrams have been made with Excalidraw. When the user presses the button to load a module, the entire chunk will be requested over the network and when it is ready, the module requested by the user will be executed and retrieved. The value here can be anything except a function. Additional tools: None. Because foo could potentially be any path to any file in your system or project. How do I return the response from an asynchronous call? Once the npm run build is run, the dist directory should have 2 files: main.js, which is the main chunk, and animal.js, which is the chunk in which all the modules corresponding to the files inside the animals/ directory reside. The map's keys are the IDs of the chunks and the values depend on the chunk's status: 0(when the chunk is loaded), Promise(when the chunk is currently loading) and undefined(when the chunk hasn't even been requested from anywhere). // And here the chunk is loaded. The example this section is based on can be found here(make sure to also start the server). The compiler ensures that each dependency is available. Geoff Miller 84 Followers Frontend Engineer @ Signifyd.com (we are hiring!) The ES2015 Loader spec defines import() as method to load ES2015 modules dynamically on runtime. I got a folder with hundreds of SVGs in it. Would anyone have any ideas as to why webpack wouldn't create the chunk files? This is the same for core-js@2, except the imports paths are slightly different: --save-dev @babel/plugin-syntax-dynamic-import, --dev @babel/plugin-syntax-dynamic-import, babel --plugins @babel/plugin-syntax-dynamic-import script.js, Working with Webpack and @babel/preset-env. https://webpack.js.org/guides/code-splitting/#dynamic-imports, https://babeljs.io/docs/plugins/syntax-dynamic-import/#installation. Dynamic Import from external URL will throw Module not found error. Lets now explore those strategies in greater detail. How can I remove a specific item from an array in JavaScript? This CANNOT be used in an async function. - A preloaded chunk starts loading in parallel to the parent chunk. But for this article, Im going to use the proposed ES2015 dynamic imports supported by Webpack, since the v2, through a babel plugin and the extra specific Webpack features for it. There are no special prerequisites, apart from a basic understanding of how the import function behaves when its argument is static(i.e it creates a new chunk). To recap: Webpack's placeholders allow you to shape filenames and enable you to include hashes to them. If dependencies are not provided, factoryMethod is called with require, exports and module (for compatibility!). Making statements based on opinion; back them up with references or personal experience. [11] ./sources/views/timeclock.js 2.92 KiB {0} [built] // The user is supposed to type an animal name and when the button is pressed. Using docker volume properly will lead to higher productivity. If the current behavior is a bug, please provide the steps to reproduce. The generated code should be __webpack_require__.t(m, 6) instead of 7, If someone wants to send a PR the problem is somewhere in RuntimeTemplate.js probably in namespacePromise. Notice how the chunk depends on the animal name. Check out the guide for more information on how webpackPreload works. Find centralized, trusted content and collaborate around the technologies you use most. Similar to require.resolve, but this won't pull the module into the bundle. Recovering from a blunder I made while emailing a professor. I'm creating react component libraries, which I'm then using to lazy load as routes, but while this works with a static import: const LazyComponent = lazy(() => import('my-package')), const packageOne = 'my-package' My problem was closely related to #7417, @younabobo It is documented, we can't build module from x, it is runtime value and it is impossible to detect https://webpack.js.org/api/module-methods/#dynamic-expressions-in-import, @ufon You need this #11127, we will implement it for webpack@5. This feature relies on Promise internally. Hey, I noticed that Webpack just put numbers to generated chunks. @evilebottnawi Please look at this repo: https://github.com/Miaoxingren/webpack-issue-8934. privacy statement. dog.js The bundle analyzer was still showing the chunk names similar to 1234.asdfd23534kjh346mn63m46.chunk.js, And to name my chunks I added magic comments similar to following on all dynamic imports in the codebase. The most valuable placeholders are [name], [contenthash], and . Thank you for looking at this maksim. [contenthash].chunk.js, But still no luck! The text was updated successfully, but these errors were encountered: That part wraps the result in a namespace object as import() always returns a namespace object. To learn more, see our tips on writing great answers. [0] ./node_modules/css-loader!./node_modules/less-loader/dist/cjs.js!./sources/styles/anytime.css 1.18 KiB {0} [built] rev2023.3.3.43278. Time: 2813ms Only modules that match will be bundled. The following CommonJS methods are supported by webpack: Synchronously retrieve the exports from another module. What Is the Difference Between 'Man' And 'Son of Man' in Num 23:19? If the module source contains a require that cannot be statically analyzed, critical dependencies warning is emitted. [10] ./sources/views/admin/subscriptions.js 9.79 KiB {0} [built] In the previous section we've seen how to manually specify the mode, so the way to tell webpack we want to use the lazy-once mode should come as no surprise: The behavior in this case is somehow similar to what we've encountered in the previous section, except that all the modules which match the import's expression will be added to a child chunk and not into the main chunk. The following methods are supported by webpack: Statically import the exports of another module. webpack version: 4.25.1 webpack.config.js. Technically, you could stop here and officially have done code splitting! The nature of simulating nature: A Q&A with IBM Quantum researcher Dr. Jamie We've added a "Necessary cookies only" option to the cookie consent popup. @Miaoxingren Please create minimum reproducible test repo. I have been following the SO questions and implemented something similar to this answer in a React + Webpack project. I am trying to setup dynamic svg imports since my app uses many icons and I don't want to impact startup time to load all icons i.e. The goal of CommonJS is to specify an ecosystem for JavaScript outside the browser. It's what is considered a "weak" dependency. Version: webpack 4.28.2 To learn more, see our tips on writing great answers. This feature relies on Promise internally. I was trying to optimize the React App and as we already have splitChunks in our webpack configuration, it was for granted to pay more attention to code splitting. + JSON.stringify(babelSettings). Already have an account? Well occasionally send you account related emails. Dynamic import is the way to import some chunk of code on demand. require.ensure([], function(require) { require('someModule'); }). What sort of strategies would a medieval military use against a fantasy giant? What webpack does in this case is to keep track of whether modules that match the import's expression exist or not and also keep track of modules' exports type, if needed(e.g if they are all ES modules, then there is no need for it). reactjs ComponentA myComponents ComponentA adsbygoogl React.lazy handles this promise and expects it to return a module that contains a default export React component. Operating System: windows Still no luck ?.Magic Comments are not reaching Webpack. Now it works. This can be verified in our example: after starting the server, try to require any of the modules present in the animals directory. Webpack 3, Dynamic Imports, Code Splitting, and Long Term Caching Made Easy. Secure websites are necessary requirements. We will see what is meant by that in the following sections, where we will examine the customizations the import function can accept. In old versions of Webpack (v1), we commonly used the AMD require or the specific Webpack require.ensure to dynamic load modules. If you think this is still a valid issue, please file a new issue with additional information. ), Yeah there really seems something wrong here. See the spec for more information and import() below for dynamic usage. You might be wondering now: isn't it a waste of resources, if webpack creates multiple chunks when in the end there will be only one chunk that matches the path? JavaScript heap out of memory in angular 2, NodeJS - FATAL ERROR: CALL_AND_RETRY_LAST Allocation failed, Javascript heap error when nativescript application bundled with webpack, Build Angular App on Rasperry Pi causes Ineffective mark-compacts near heap limit Allocation failed - JavaScript heap out of memory.