A main point of his talk is automating things in software projects. Instala o Prettier no desenvolvimento yarn add prettier eslint-config-prettier eslint-plugin-prettier -D Alterar o arquivo eslintrc.js Adicionar o arquivo .prettierrc aplica as correcoes em todos os arquivos JS na pasta SRC yarn eslint --fix src --ext .js Plugin EditorConfig para o VSCode Gerar arquivo de configuracao, conforme anexo ou commit Use single quotes instead of double quotes in JSX. Developers often use whitespace to break up long lines for readability. eslint-config-prettier. Doing so produces a large git diff and thus makes the line-by-line history for a file (git blame) harder to explore. This will make sure all ESLint … eslint-plugin-prettier plugs Prettier into your ESLint workflow; eslint-config-prettier turns off all ESLint rules that are unnecessary or might conflict with Prettier Specify the global whitespace sensitivity for HTML files, see whitespace-sensitive formatting for more info. Tab Width - how many spaces you want a tab to consist of; Open the settings menu as above. (Most Style-Guides set there tab-width at (2x Space-Width), but many dev's will change there settings to a (4x Space-Width). (Tabs will be used for indentation but Prettier uses spaces to align things, such as in ternaries.). ! First available in v1.9.0, default value changed from avoid to always in v2.0.0. Any thing other than 2x and 4x is considered taboo.) It doesn’t make sense to use it in a configuration file. It is also possible for Windows users to accidentally change line endings in a previously committed file from LF to CRLF. The prettier configuration will override any prior configuration in the extends array disabling all ESLint code formatting rules.With this configuration, Prettier and ESLint can be run separately without any issues. Now, whenever you open a new file with your editor, the indentation will already be configured at 4. A common mistake is to forget our ESLint-Prettier pattern and apply this rule within the .eslintrc.json file like so: The generated error should be of no surprise to you if you followed everything that was said before. ESLint also highlights formatting issues, but since it’s a lot more configurable, everyone could have a different set of formatting rules. If you change any options, it’s recommended to do it via a configuration file. Since TSLint will soon be deprecated, we decided to replace it with ESLint. If the number of quotes outweighs the other quote, the quote which is less used will be used to format the string - Example: Backwards to the start of the first line containing the selected statement. Some details explaining why it is so can be found on Wikipedia. Custom parsers are also supported. Prettier is an opinionated code formatter. Flow, TypeScript 3. Prettier’s printWidth option does not work the same way. Markdown and with pluginsyou can use it for Python, PHP, Swift, Ruby, Java and more. They are slower than running Prettier directly. This will bring up all of the settings that you can change right there in your editor. It took me some time to figure it all out. Fortunately for us, the eslint-config-prettier package already does that. Using eslint and prettier have become standard best practices for javascript projects to maintain consitency in the code base. Tips. That is \n (or LF for Line Feed) and \r\n (or CRLF for Carriage Return + Line Feed). However, old versions of Notepad for Windows will visually squash such lines into one as they can only deal with \r\n (CRLF). (If you don’t want line wrapping when formatting Markdown, you can set the Prose Wrap option to disable it.). This setup is all nice and good with this kind of small project but eventually, when one starts to use Vue, React or other frameworks, it becomes very easy to mess with both the ESLint and Prettier configurations. I don’t write the best-looking code, but with Prettier I no longer have to worry about that. The process of having to run two commands to lint and format our file is not very convenient. There is a lot of logging available with prettier-eslint.When debugging, you can use one of the logLevels to get a better idea of what's going on. If you decide to use ESLint with Prettier rules and have configured husky to run lint-staged, point it at eslint --fix instead of prettier --write. It is a way to say to Prettier roughly how long you’d like lines to be. When people collaborate on a project from different operating systems, it becomes easy to end up with mixed line endings in a shared git repository. Put the > of a multi-line JSX element at the end of the last line instead of being alone on the next line (does not apply to self closing elements). Pretty easy right? It just does not seem to recognize any sort of printWidth at all (i.e. The advantage of having prettier setup as an ESLint rule using eslint-plugin-prettier is that code can automatically be fixed using ESLint's --fix option.. If we run ESLint with --fix flag, it will use Prettier to auto format code, solving both stylistic and semantic problems.. Prettier can restrict itself to only format files that contain a special comment, called a pragma, at the top of the file. These two options can be used to format code starting and ending at a given character offset (inclusive and exclusive, respectively). Prettier does nothing to help with those kind of rules. If we run ESLint with --fix flag, it will use Prettier to auto format code, solving both stylistic and semantic problems.. You will notice this at the bottom right of the editor: However, this means that Prettier and EditorConfig share some configuration options that we do not want to repeat in two separate configuration files and keep them in sync (e.g. max-len just says what the maximum allowed line length is, but not what the generally preferred length is – which is what printWidth specifies. We then modify our .eslintrc.json file to incorporate TypeScript by adding the TypeScript parser in the parser option and by adding the plugin to our extends array: We then try ESLint on our file with the fix option: And if we run the command multiple times, we get the same error even though the console says the errors can be fixed. JavaScript 2. If you have already used Prettier alongside ESLint, you probably encountered problems with your code formatting. With this type of configuration, I think it would be best not to adopt a setup once and forget approach for your linting and formatting experience. Why You Should Use ESLint, Prettier & EditorConfig. The aim of this post is to provide guidelines on how to configure ESLint, Prettier and EditorConfig without any conflicts while also avoiding redundant configuration. CONFIGURATION WELCOME. ??? JSON 7. Our code looked like this: After a lot of investigating, we managed to make ESLint and Prettier coexist and work together. We will now rewrite our .eslintrc.json file by adding the prettier plugin in the plugins array and setting the newly established prettier rule to error so that any prettier formatting error is considered as an ESLint error. The process of having to run two commands to lint and format our file is not very convenient. EditorConfig supports a variety of editors. For example, after running Prettier against a JavaScript file with the default configuration, all tabs would be changed to a width of 2 spaces, and double quotes would be replaced with single quotes. Since this is an editor relevant configuration, we should add it to the .editorconfigfile. Then save my file. Note: the default value was "babylon" until v1.13.0. Prettier ships with a handful of format options. In order to be able to use ESLint alongside Prettier, the idea is to deactivate all ESLint rules that might conflict with Prettier (code formatting rules). I don’t want semicolons and I prefer single quotes to double quotes for strings. I am not sure which package / extension causes this issue, but sometimes there seems a conflict between eslint and prettier in tab width formatting. But two problems appear: If we follow the pattern described above, no code formatting should be done by ESLint and the newly added plugin is no exception to this pattern. This is very useful when gradually transitioning large, unformatted codebases to prettier. You need to explicitly tell them what to do, while humans can make their own (implicit) judgements, for example on when to break a line. Using eslint and prettier have become standard best practices for javascript projects to maintain consitency in the code base. However, when Prettier removes parentheses, it becomes harder to add type annotations, extra arguments or default values as well as making other changes. In terminals with support for hyperlinks, Command-click the rule ID to open its docs. Prettier ships with a handful of format options, some of them are: Tab Width; Tabs; Semicolons; Quotes We add ESLint and Prettier to our project as dev dependencies so that we can compare both tools on the same file.. npm install eslint prettier --save-dev. For historical reasons, there exist two common flavors of line endings in text files. In this particular case, ESLint will be our code quality linter, Prettier our code formatting tool while EditorConfig will provide everyone with the right editor configuration. ESLint+Prettier统一TypeScript代码风格. We have the exact same error as in the previous issue with a conflict between Prettier and ESLint: To follow this pattern, all code formatting rules should be set within Prettier's configuration in the .prettierrc file. In practice, the average line length often ends up well below the maximum. 想在团队中推行一定的代码规范，并给不符合规范的代码做检测和提示。 It is therefore of the utmost importance that prettier and prettier/@typescript-eslint are at the end of the array. Once you’ve installed ESLint, you can install the Prettier plugin called eslint-plugin-prettier, and it works for all code editors.This plugin runs Prettier as an ESLint rule and reports differences as individual ESLint issues. We also add a simple .eslintrc.json configuration to add ESLint recommended rules. Change when properties in objects are quoted. (Tabs will be used for indentation but Prettier uses spaces to align things, such as in ternaries.). It takes an option as the second parameter which can be "tab"for tab-based indentation or a positive number for space indentations. NOTE: auto-fixing will only convert invalid indent whitespace to the desired type, it will not fix invalid whitespace sizes. Developer @Theodo. The issue appears to happen for me only when the ESLint Integration option is enabled.However, all of my other ESLint rules appear to be working fine. I want tab width of 2 spaces. You will see that our file gets formatted the same way Prettier did. So if the ESLINT Airbnb linting rules contain formatting rules, they will have to be disabled if you do not want any conflicts with Prettier. When running this, you will get a dialog of questions. This applies more to ESLint than Prettier (because of Prettier’s defaults), but I’d recommend a .prettierrc file specific to a project for a team. It supports many languages and integrates with most code editors. The most important links you need to know more a… In some cases you may want to rely on editor/viewer soft wrapping instead, so this option allows you to opt out with "never". Prettier工具少数几个可以定制的参数，在CLI命令行和配置文件中均可用。 Print Width. Both the babel and flow parsers support the same set of JavaScript features (including Flow type annotations). Prettier is supposed to make you forget about formatting – and not be in your face about it! Fan of VueJS and TypeScript! Prettier is an opinionated code formatter. I want to use tab as indentation and want the size of the tab to be four, for which I set my user settings and workspace settings as shown in following screenshots: As you can see I set 'prettier.useTabs' to true and 'prettier.tabWidth' to 4. There are several common guidelines which require specific indentation … If you wish to modify your configuration, you will have to remember following the pattern described above. Default value changed from none to es5 in v2.0.0, Print trailing commas wherever possible when multi-line. JavaScript--no-semi--jsx-single-quote--jsx-bracket-same-line--quote-props --arrow-parens --trailing-comma . For example, the following will use the CSS parser: This option is only useful in the CLI and API. Prettier has configuration options if you want to do anything outside of set a line width or a indentation size, you're out of luck. Finally, we have tools that runs prettier and then immediately for example eslint --fix on files. Similar to ESLint, Prettier allows you to customize formatting options such as line width, tab width, semicolons, quotes, brackets, and several more. It integrates with the most popular code editors, including VS Code, Sublime Text, Atom and more. I think that it's going to be a subtle, but positive, change for 80 columns … ESLint fix runs with lint-staged library on staged file 3)Now lets setup “Prettier” to format our code Install Prettier. Prettier is hugely popular, as in February 2018 it has been downloaded over 3.5 million times. Most code conventions require either tabs or spaces be used for indentation. Enforcing eslint and prettier using husky git hooks is a great way to ensure that quality with minimal developer effort. On one of our TypeScript-React projects, we decided to use ESLint and Prettier to both lint and formatour code. First available in v1.15.0, default value changed from auto to lf in v2.0.0. We take our unlinted main.js file and apply ESLint on it: We can see that the lines that have too many characters or bad indentation, are marked by prettier/prettier as errors within our ESLint error output. Print spaces between brackets in object literals. On top of this, we even decided to add EditorConfig to the mix! This works well when used in tandem with the --require-pragma option. I encountered these issues at work when we decided to migrate from TSLint to ESLint on one of our TypeScript projects. JSX 5. If you would like to change any other options to match your liking, checkout the options page on the prettier website. This is a fork of prettier/prettier, with an option added to indent lines with tabs.If you have a simple option you want to add to Prettier With Tabs, send a PR! For example, I don't like javascript code without semicolons, but if you can send me a PR which add this ability with as little code as possible, I'll happily accept it! It is opinionated. You can replace all the prettier relevant configuration we made in our .eslintrc.json file by adding the plugin:prettier/recommended configuration in the extends array. If you would like to easily format your entire project, add the following to the to the "scripts" field of your package.json. In this article, we will use VSCode but keep in mind that EditorConfig supports a variety of editors. If you would like to easily format your entire project, add the following to the to the "scripts" field of your package.json. The former is common on Linux and macOS, while the latter is prevalent on Windows. Start by adding Prettier as an ESLint rule using this first command in the terminal, followed by installing Prettier itself. Will accept a PR for eslint 6 support otherwise I'll try and get to it in a couple of weeks as I'm on vacation currently. Include parentheses around a sole arrow function parameter. At first glance, avoiding parentheses may look like a better choice because of less visual noise. well-known solution to enforce a consistent coding style along a project If you followed what we have done until now, you might notice a configuration error. ; false - Only add semicolons at the beginning of lines that may introduce ASI failures. The second method is to run Prettier from ESLint. At some point in the project above, we decided to use TypeScript. It looks like the error comes from a @typescript-eslint rule. CSS, SCSS, Less 4. For the rest of this post, we will use the code already written in the first article. Use single quotes instead of double quotes. The length of a line is defined as the number of Unicode characters in the line. Prettier is an opinionated code formatter. Prettier automatically infers the parser from the input file path, so you shouldn’t have to change this setting. What we do below is applicable to React, Vue or any other frameworks that have an ESLint plugin available. For our project above, the team is not comfortable with 2 space indentation and wants to switch to 4. Prettier and ESLint are two different tools. Prettier will not have to format your code for this setting. Common--single-quote--no-bracket-spacing--prose-wrap . We patched the issue above by adding an ESLint rule forcing two space indentations. Validate Indentation (indent) This option validates a specific tab width for your code in block statements. When Prettier identifies cases where it looks like you've placed some code it knows how to format within a string in another file, like in a tagged template in JavaScript with a tag named html or in code blocks in Markdown, it will by default try to format that code. Whether or not to indent the code inside