However, I noticed they're not being utilized to their fullest potential. Usually, you dont need this rule at all. This rule can be used with certain options. Note that this config only turns rules off, so it only makes sense using it together with some other config. Prettier generally preserves the way you wrote your elements: But for known void HTML elements, Prettier always uses the self-closing style. Finally, we need to update the env property to include node since Next.js supports Server Side Rendering in Node. The file should be formatted according to Prettier, and that formatting should disagree with the plugin. Usually youll have about the same rules for all files, so it is good enough to run the command on one file.
Some require certain options. But if you use multiple configuration files or overrides, you can provide several files check: eslint-config-prettier versions before 7.0.0 had a slightly different CLI tool that was run in a different way. How to Setup your Next.js Project using ESLint and Prettier. Create the .prettierrc.js file and modify it like the below. Check out eslint-plugin-prettiers recommended config. Note: if you do not already have TypeScript configured then your linter will fail. If a block (for example after if, else, for or while) contains only one statement, JavaScript allows omitting the curly braces around that statement. Done! That includes all plugins. * file. Have new rules been added since those versions? For example: eslint-config-prettier also ships with a little CLI tool to help you check if your configuration contains any rules that are unnecessary or conflict with Prettier. Ending up with an accidental sequence expression can easily happen while refactoring. I have explained most use cases for the following plugin, in this post. For Next.js, I'm going to divide this article into two sections, based on complexities and the number of plugins we have to integrate into the project: First install the ESLint and Prettier using following commands: Following is the Prettier setting I use in my projects and this remains same for the Pro Setup as well. Prettier breaks it up into several lines, though, causing a conflict: If you like this rule, it can usually be used with Prettier without problems, but occasionally you might need to either temporarily disable the rule or refactor your code. Note: You might find guides on the Internet saying you should also extend stuff like "prettier/react". This rule forbids using JavaScripts confusing comma operator (sequence expressions). Some require special attention when writing code. (Which is nice simplifying your config! You can use the applications that are created by this blog writer. The quotes rule has two options, a string option and an object option. Otherwise Prettier might reformat your code in such a way that ESLint never gets a chance to report anything (as seen in the first example). You can see the full source code of this blog post on the following link. Several blank lines in a row are collapsed into a single blank line. The react/react-in-jsx-scope rule will throw an error if a component files not import React. You can check out my article on Eslint made easy breaking down Eslint for you. To forbid backticks where regular strings could have been used. If you want to check other blog posts of the series, see the links below. Create a file called .eslintignore at the root of your project with these contents: The scripts property in your package.json can be updated to add a lint script to make linting easier: In this lint script we are calling the ESLint CLI, telling it to lint files under the current folder (./), and looking for files with the extensions js, jsx, ts, or tsx. no-sequences can safely be disabled if you use the no-restricted-syntax approach. These rules dont conflict with Prettier, but have some gotchas when used with Prettier. The CLI helper tool validates this. These rules might cause problems if using eslint-plugin-prettier and --fix. This command will prompt you for a series of questions: You should now have an .eslintrc. In theory you need to run the tool for every single file in your project to be 100% sure that there are no conflicting rules, because ESLint supports having different rules for different files. Start a clean Next.js project with TypeScript, ESLint and Prettier from scratch, Start a clean Next.js project with TypeScript, ESLint and Prettier from scratch, Select whether your project uses TypeScript. ESLint can now be used with the following commands: The commands above will only lint the files inside pages/, but you can customize this however you see fit. It doesnt hurt to explicitly set {allowParens: false} even though it is technically redundant. Now, add the following to your .eslintrc.js file, and you are good to go. trailingComma: all: To make small changes, if the comma can be added, add the comma to the last. Notion template to track all your new year goals.
Now that we have ESLint working properly with Next.js, we need to add a file to tell ESLint to ignore certain files that we do not want linted. * file generated at the root of your project. prettier --write --ignore-path .gitignore . Eslint and Prettier, are the most used npm packages in all Modern JavaScript Applications. Note: If you do enable this rule, you have to run ESLint and Prettier as two separate steps (and ESLint first) in order to get any value out of it. ESLint requires a config in the root of the project, which can be easily generated with the CLI. In other words, if you run eslint --fix and prettier --write as separate steps. Open an issue or a pull request! Usually, Prettier takes care of following a maximum line length automatically. For maximum ease of use, the special rules are disabled by default (provided that you include all needed things in "extends"). If you have same problem, please try to add Prettier to your Next.js project. If prompted to install dependencies, click. Prettier preserves blank lines, with two exceptions: By default, ESLint requires a blank line above the comment is this case: However, Prettier removes the blank line: If you like this rule, it can be used just fine with Prettier as long as you add some extra configuration to allow comments at the start and end of blocks, objects and arrays. Next, we need to configure the Prettier to use it. While we can use prop-types with Next.js, TypeScript is typically preferred. If you run ESLint as-is then you'll likely have some linting errors.
If youd like to add support for eslint-plugin-foobar, this is how youd go about it: test-lint/foobar.js must fail when used with eslint-plugin-foobar and eslint-plugin-prettier at the same time until "prettier/foobar" is added to the "extends" property of an ESLint config. to your .eslintrc.js , and you're good to go : The main difference setting Pro apart from The Basic setup, is that the Pro flaunts a few more plugins, more awesome and customizable ones . This helps catching typos, for example. For example: If you find something like that in a tutorial, this is what the command looks like in 7.0.0 or later: There a few rules that eslint-config-prettier disables that actually can be enabled in some cases. You signed in with another tab or window. Finally, you need to mention the plugin in several places: When youre done, run npm test to verify that you got it all right. Add the following config. Also we have weekly discussion on dev.to every Wednesday and Saturday. ), (Change path/to/main.js to a file that exists in your project.). Thanks again, if you have any queris reach out to me @sarthology. There are a couple of ways to turn these rules off: It doesnt matter which approach you use. // `plugin:foobar/recommended` wants one. This blog post is a series. This lets you use your favorite shareable config without letting its stylistic choices get in the way when using Prettier. I personally prefer JSON. This rule disallows confusing multiline expressions where a newline looks like it is ending a statement, but is not. After all files are fixed, execute the following command again. For now, let's focus on quickly setting up Next.js. Step by Step guide. That can be used just fine with Prettier as long as you dont configure Prettier to indent using tabs. Prettier (this is the default, so adding this is not required): This rule enforces whether elements should be self-closing or not. In this blog post, I will introduce how to configure Prettier in the Next.js project based on TypeScript. You can also specify multiple directories: pages/* components/*. This rule forbids mixing certain operators, such as && and ||. So, I decided to use Prettier in Next.js to solve this problem. Some of the rules that eslint-config-prettier turns off may be deprecated. If youd like to enforce an even stricter maximum line length policy than Prettier can provide automatically, you can enable this rule. This may lead to conflicts. (Thats how ESLint works it lets you override configs you extend.) It runs several other npm scripts: This commit does not belong to any branch on this repository, and may belong to a fork outside of the repository. Blank lines at the beginning and end of blocks, objects and arrays are always removed. , Basic Boilerplate Setup of Next.js, ESLint and Prettier - sarthology/next-js-eslint-basic, Pro Boilerplate Setup of Next.js, ESLint and Prettier - sarthology/next-js-eslint-pro, Learn JavaScript sync and async the easy way , Drag and Drop Image Upload with HTML5 and ES6, Storybook Js with Next Js and Tailwind CSS. If you want them, you need to explicitly specify them in your ESLint config. To enforce the use of backticks rather than single or double quotes for strings. For example, the "multi-line" option allows this line: However, Prettier might consider the line too long and turn it into the following, which the "multi-line" option does not allow: If you like this rule, it can be used just fine with Prettier as long as you dont use the "multi-line" or "multi-or-nest" option. See the arrow-body-style and prefer-arrow-callback issue for details. Checkout this document for further details on more options available. If youd like ESLint to enforce `could have been a regular string` being written as either "could have been a regular string" or 'could have been a regular string', you need to use some specific configuration. If you like this rule, it can be used just fine with Prettier as long as you set html.void to "any". But there are two cases where it could be useful: If youd like all strings to use backticks (never quotes), enable the "backtick" option. (The following applies to vue/max-len as well.). We add the .gitignore file to the --ignore-path option to ignore the files not managed by Git. Since Prettier automatically wraps them in parentheses, you might never see any warnings from ESLint about comma operators. arrow-body-style and prefer-arrow-callback, eslint-plugin-prettiers recommended config. Those need to be split up by a human. Extending "prettier" turns off a bunch of core ESLint rules, as well as a few rules from these plugins: Using eslint-plugin-prettier? The rule suggests adding parentheses, like this: However, Prettier removes many unnecessary parentheses, turning it back to: If you want to use this rule with Prettier, you need to split the expression into another variable: Keep in mind that Prettier prints some unnecessary parentheses, though: This rule disallows the use of tab characters. The tool will produce a warning if you use the default even if you use an older version of ESLint. Then, add "prettier" to the "extends" array in your .eslintrc. To see how to apply Prettier to the Next.js projecct, execute the following command to create a Next.js project with TypeScript. Make sure to put it last, so it gets the chance to override other configs. A combination of notion and classic bullet journal. The first thing we need to fix is the warning: Warning: React version not specified in eslint-plugin-react settings. By default the rule forbids all tab characters. First, we need to install these ESLint dependencies: eslint is the CLI and main package responsible for linting your project. This piece of code is not doing what it looks like: Prettier adds parentheses to the above to make it clear that a sequence expression is used: However, the no-sequences rule allows comma operators if the expression sequence is explicitly wrapped in parentheses. If all files are fixed well, you can see the following message. The second (object) option needs the following properties: Add eslint-plugin-foobar to the "devDependencies" field in, Make sure that at least one rule from eslint-plugin-foobar gets used in, Add it to the lists of supported plugins and in this. It works as your third eye, protecting your project from that sneaky smelly code, from being pushed into, or committing to - forcing people to follow the guidelines added by you. Please leave a comment at the bottom. Was my blog helpful? Prettier is a code formatting tool to manage the same code style. eslint-plugin-react is a plugin for ESLint with rules specific to React. * file. By default, Next.js does not come with any linting solution. I normally use VSCode with the Prettier plugin, and when I saved the modificated files, the semicolon and double quotes are automatically added. This is the setup I personally use, in all my Next.js projects. Let's add a few more of these popular plugins, and get you started with having Basic Linting in your project . Containing bonus boilerplate templates also, to help you get started. This rule requires special attention when writing code. Finally, run the CLI helper tool to find problems in the "rules" section of your .eslintrc.
Remove them from your config or turn them off manually. This rule requires empty lines before and/or after comments. However, there are cases where Prettier cant do anything, such as for long strings, regular expressions and comments. Since version 8.0.0 of eslint-config-prettier, all you need to extend is "prettier"! Just remember to keep max-lens options and Prettiers printWidth option in sync. For more information on using the CLI, visit the official documentation. The CLI helper tool reports that "indent" conflicts with Prettier, so you can remove it. In the following example, the first array item could have been written with quotes instead of backticks. weve seen how to configure Prettier to the Next.js project. That no unknown rules are turned off. This rule enforces if or when those optional curly braces should be omitted. To get rid of this, we can add settings property at the root of our config: Open the ESLint config that was generated and edit the rules object: The react/prop-types rule enforces that all components have prop-types defined. Turns off all rules that are unnecessary or might conflict with Prettier. Select what format you want the ESLint config to be in. I will be posting few more articles in this Next Station series of Next.js, so subcribe to get notified. ESLint 101: The simplest and shortest guide to getting started with ESLint. The CLI helper tool warns you if any of those rules are enabled, but cant tell if anything is problematic. I encourage you to edit this file as per your preferences. This is fine. it will be a great help to me! The first (string) option needs to be set to. This example has a conflicting rule "indent" enabled: While the "prettier" config can disable problematic rules in "some-other-config-you-use", it cannot touch "rules"! To fix this, we need to update the ESLint config rules to fit Next.js. This is perfectly fine, but if you really need to omit the deprecated rules, you can do so by setting the ESLINT_CONFIG_PRETTIER_NO_DEPRECATED environment variable to a non-empty value. With React 17, which Next.js now ships with, it is no longer necessary to import React and thus this rule can be disabled. If you want ESLint to catch such mistakes, it is recommended to forbid sequence expressions entirely using no-restricted-syntax (as mentioned in the no-sequences documentation): If you still need to use the comma operator for some edge case, you can place an // eslint-disable-next-line no-restricted-syntax comment on the line above the expression. You can fix the code style automatically by executing the command below. To use the Prettier that weve set, open the package.json file and modify it like the below. ESLint Getting started If there is any file violated by the Prettier rules, you can see the error message like the below.
Note: The CLI tool only reports these as problematic if the "prettier/prettier" rule is enabled for the same file. For example, is turned into
. This rule requires certain options and certain Prettier options. Husky gives you the ability to add precommit hooks. (Note: The CLI helper tool considers {allowParens: true} to be the default, which is the case since ESLint 6.0.0. Keep in mind that you might have to refactor code slightly if Prettier formats lines in a way that the max-len rule does not approve of. Now, execute the command below to check the code style with Prettier. prettier --check --ignore-path .gitignore . These rules are safe to use if you dont use eslint-plugin-prettier. This way Prettier takes care of your indentation, while the no-tabs takes care of potential tab characters anywhere else in your code. You can also supply a custom message if you want: See package.json for the exact versions of ESLint, Prettier and ESLint plugins that eslint-config-prettier has been tested with. after that, add this to your package.json file: Hopefully, you have learned something new here. (Remember, "rules" always wins over "extends"!). Luckily, its possible to configure the rule so that it works regardless of whether Prettier uses spaces or tabs: Set allowIndentationTabs to true. (The following applies to babel/quotes and @typescript-eslint/quotes as well.).