webpack dynamic import not working

Find centralized, trusted content and collaborate around the technologies you use most. Get the latest coverage of advanced web development straight into your inbox. Reading has many benefits, but it takes a lot of work. Therefore, I think it's definitely a bug. Note that setting webpackIgnore to true opts out of code splitting. 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. Lazy Loading is a hot topic for the optimization of web applications. It allows code to render synchronously on both the server and initial page-loads on the client. Dynamic Import from external URL will throw, v2 Addon Format (Embroider compatibility), Dynamic Import not working with variable path. This can be verified in our example: after starting the server, try to require any of the modules present in the animals directory. Keep in mind that you will still probably need babel for other ES6+ features. Connect and share knowledge within a single location that is structured and easy to search. This is the default mode, meaning that you don't have to explicitly specify it. The given expression can have multiple dynamic parts. 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. Have a question about this 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. Would anyone have any ideas as to why webpack wouldn't create the chunk files? How do I remove a property from a JavaScript object? Now it works. All the following sections will be based on the same example where there is a directory called animals and inside there are files that correspond to animals: Each examples uses the import function like this: import('./animals/${fileName}.js'). By using weak imports, we're essentially telling webpack that the resources we want to use should already be prepared for retrieval. Using it in an async function may not have the expected effect. Ive tried several different variations of the imports. 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). The following is tested with Webpack 2, but should also work with v.1. You can safely remove this plugin from your Babel config if using @babel/core 7.8.0 or above. I have a component repository with a lot of pages in my app!. Now if we want to use the lion module, I should not see a new request, but only a confirmation that the lion module has been executed: Here's a diagram to supplement what's been accumulated so far: We've saved this section until last because of its peculiarities. When the asset's content changes, [contenthash] will change as well. // Here the user chooses the name of the file. The compiler ensures that each dependency is available. How to resolve dynamic import from node_modules? But as Uncle Ben once said: Know how the tool works in essential to use its maximum performance, and I hope I helped you to know a little more about it now! You put it in like so: "syntax-dynamic-import". If you want to follow along, you can find a StackBlitz demo here(it's safe to run npm run build first). Can you write oxidation states with negative Roman numerals? 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. 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? (not not) operator in JavaScript? I'm trying to migrate my app to webpack 4. What sort of strategies would a medieval military use against a fantasy giant? require.ensure() is specific to webpack and superseded by import(). Make all exports from the dependency available in the current scope. *\\.js$/ and it will be tested against all the files which reside in the animals/ directory(e.g regExp.test('./cat.js')). To subscribe to this RSS feed, copy and paste this URL into your RSS reader. I thought of analyzing our bundle with Webpack Bundle Analyzer and seeing how splitChunks has done the splitting. If the current behavior is a bug, please provide the steps to reproduce. React.lazy handles this promise and expects it to return a module that contains a default export React component. Modules are reusable chunks of code built from your app's JavaScript, node_modules, images, and CSS styles, which are packaged to be easily used on your website. Old solution A solution is to use node --max_old_space_size=8000 scripts/start.js to get it working. Lets now explore those strategies in greater detail. 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. The import() must contain at least some information about where the module is located. Including hashes related to the file contents to their names allows to invalidate them on the client-side. dog.js CommonJS or AMD modules cannot be consumed. Dynamic imports syntax is recently introduced in the language and hence is not a standard yet. @sokra @evilebottnawi Any updates on this issue? Let's solve solution for this, @Miaoxingren reproducible repo still has the problem? The following methods are supported by webpack: import Statically import the export s of another module. */ by default(you can think of it as a glob pattern). You put it in like so: "syntax-dynamic-import". Consider the following example: The StackBlitz app for this example can be found here. It's able to require modules without indicating they should be bundled into a chunk. The callback will be called with the exports of each dependency in the dependencies array. While webpack supports multiple module syntaxes, we recommend following a single syntax for consistency and to avoid odd behaviors/bugs. Sign up for a free GitHub account to open an issue and contact its maintainers and the community. This is because webpack can't know during the compilation what modules will be imported. Although it worked with webpack@3. Ive read everything I can find in the webpack documentation and every relevant link Google produces for two days with no luck. See this thread to the problem https://github.com/webpack/webpack/issues/5747. Based on the module's exports type, webpack knows how to load the module after the chunk has been loaded. How do you ensure that a red herring doesn't violate Chekhov's gun? https://github.com/webpack/webpack/issues/5857#issuecomment-338118561, GitHub - airbnb/babel-plugin-dynamic-import-webpack: Babel plugin to transpile import() to require.ensure, for Webpack, Babel is configured to NOT remove the comments. This feature relies on Promise internally. The upside of this way of loading modules is that you don't overload the main chunk with all the possible modules that can match the import's expression, but rather they are put in another chunk which can be loaded lazily. Dynamic import is the way to import some chunk of code on demand. 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". Which you can see here: GitHub - airbnb/babel-plugin-dynamic-import-webpack: Babel plugin to transpile import() to require.ensure, for Webpack. webpackExclude: A regular expression that will be matched against during import resolution. Include a dependency without executing it. In the Lib project: Create an entry point file, say index.js, that exports all the custom React components like this: import {Button} from './button'; import {DatePicker} from . But Webpack can detect files to bundle when it is given a string interpolation in require() like: import(/* webpackIgnore: true */ "https://maps.googleapis.com/maps/api/js?v=3.exp&signed_in=true&libraries=places&key=" + gkey); Webpack is a static module bundler for JavaScript applications. What is the point of Thrower's Bandolier? 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. Dynamic import seems to be the solution but I'm not having any luck getting webpack to create the chunk files. to your account, What is the current behavior? In this example, the resulting RegExp object will be /^\\.\\/. @ooflorent Is it possible to import the bundle from external url in webpack for e.g. Have a question about this project? If Magic Comments (or Any Comment) are not reaching the webpack, then they are lost in the transpiling process. If a hash has changed, the client is forced to download the asset again. Note that all options can be combined like so /* webpackMode: "lazy-once", webpackChunkName: "all-i18n-data" */. If this function returns a value, this value is exported by the module. Let's learn how to enable HTTPS on localhost for a PHP application on Apache by Dockerizing it. If you use AMD with older browsers (e.g. Site design / logo 2023 Stack Exchange Inc; user contributions licensed under CC BY-SA. It's what is considered a "weak" dependency. Making statements based on opinion; back them up with references or personal experience. If you think this is still a valid issue, please file a new issue with additional information. require.ensure([], function(require) { require('someModule'); }). 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. [6] ./sources/views/admin/win_create_subsuser.js 3.24 KiB {0} [built] Time: 2813ms ), Yeah there really seems something wrong here. 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). Does a summoned creature play immediately after being summoned by a ready action? const LazyComponent = lazy(() => import(packageOne)). 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. This CANNOT be used in an async function. It's important to mention that the traversal and the file discovery are done at compile time. To get it start faster we can use webpack's cache-loader. Underlying modules can then be easily resolved later on: If mode is set to 'lazy', the underlying modules will be loaded asynchronously: The full list of available modes and their behavior is described in import() documentation. When webpack finds a dynamic import, it will assume that code should be code split and lazy loaded. Dynamic imports - this is my method of code splitting (page by page). privacy statement. However, this support does not work with dynamic import() Workaround. The following methods are supported by webpack: Statically import the exports of another module. Multiple requires of the same module result in only one module execution and only one export. The way we're currently doing things, the cat module is not loaded from anywhere else, so this is why we're facing an error. webpack it threating resolved value as module id with dynamic imports witch results with. Although it worked with webpack@3. The diagrams have been made with Excalidraw. Dynamic Import . Twice a month. But I can't get it to work. // variable will be executed and retrieved. Would anyone have any ideas as to why webpack wouldnt create the chunk files? Thanks T. I guess I cannot 'dynamically' load/include only the component I need on a pre page basis, I'll have to manually include all available componests so if they are within the 'layout' object, then they will be available. webpack version: 4.28.4 As imports are transformed to require.ensure there are no more magic comments. How can we prove that the supernatural or paranormal doesn't exist? Notice how the chunk depends on the animal name. Using it asynchronously may not have the expected effect. 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. Node.js version: 8.11.3 When using webpack to bundle your application, you can pick from a variety of module syntax styles including ES6, CommonJS, and AMD. In the Network tab, there should be a request for the animal chunk which, as stated earlier, contains all the necessary modules: Also notice that the cat module has been indeed invoked. Additional tools: -. Already have an account? 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). Recovering from a blunder I made while emailing a professor. Now the Chunks have names similar to List.asdfd23534kjh346mn63m46.chunk.js. Funny, not one tutorial told me this. At run time, when the variable language has been computed, any file like english.json or german.json will be available for consumption. // Do something with lodash (a.k.a '_') // imagine we had a method to get language from cookies or other storage, /* webpackExports: ["default", "named"] */, /* webpackExclude: /\.noimport\.json$/ */, // in theory; in praxis this causes a stack overflow, /* optional, default /^\.\/. I will first type cat and then press the button. 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). Staging Ground Beta 1 Recap, and Reviewers needed for Beta 2. // similarly to other require/import methods. Already on GitHub? As you are using [contenthash] in the output file names, only the changed modules will be cached again by service workers, not all the files. Then, if you open the dist/main.js file, you can already notice the map we talked about earlier: Once again, this object follows this pattern: { filename: [moduleId, chunkId] }. Webpack Bundler , . Geoff Miller 84 Followers Frontend Engineer @ Signifyd.com (we are hiring!) Available since webpack 5.0.0-beta.18. // Here the chunk that depends on `fileName` is loaded. The following CommonJS methods are supported by webpack: Synchronously retrieve the exports from another module. Here's my test repository https://github.com/younabobo/webpack-dynamic-import-test, @younabobo @evilebottnawi Currently, @babel/preset-env is unaware that using import () with Webpack relies on Promise internally. eg: ./locale. 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. How do I return the response from an asynchronous call? Learn 5 Optimization Tips for Webpack Step by Step Somnath Singh in JavaScript in Plain English Coding Won't Exist In 5 Years. If you are using Webpack 4.0, code splitting requires minimal configuration, Here, the return import construct is used for modules which need to be loaded dynamically.