This method works as follows:. There are a number of ways that you could get your plugin installed into an existing ESLint configuration:. Those methods were removed in the new format and should not be relied upon. The node contains all of the information necessary to figure out the line and column number of the offending text as well the source text representing the node. Keep in mind that the error level is not part of context. Each rule in ESLint has three files named with its identifier for example, no-extra-semi. This method returns an array of all the comments found in the program.

This process will repeat up to 10 times, or until no more fixable problems are found. For others, we can use different libraries that we can port over as well when we port the application. EsLint is quite a nice alternative for JsHint and is very flexible. The module returns a simple object with methods as properties. When we have this syntax tree, you could walk the structure and then write something like this for each node:.

More information on writing custom EsLint rules can be found in the offical documentation.

That’s why I wrjting sticking as close as possible to AirBnB’s guide[0], not because it’s better than anything else, it’s just that most developper seem to agree on it and it’s familiar to most dev. After applying fixes, ESLint will run all of the enabled rules again on the fixed code, potentially applying more fixes. Hacker News new past comments ask show jobs submit.

What other ideas do you have? Your engineering team has a strong preference about how to set something up, but others might choose a different option. If it is not included, should it be? On top of that we have the EsLint plugin for VsCode, which looks like this in rukes editor: This can then be plugged in to EsLint and it will report the errors for any Javascript code you throw at it. Before we start writing custom EsLint rules, I first want to show how code is analyzed and how we can plug in to that.


Writing Custom Lint Rules for Your Picky Developers

Never miss a story from Webiny Blogwhen you sign up for Medium. Lastly we want to check to see if that method is being called without arguments or a null first argument. Then you can run your new rule in isolation, for example:. They are useful for rules that need to check comments in relation to a given node or token.

This combination ensures that we clean up angular calls while we continue development and that no new calls will be introduced. As I mentioned before, if you want to share eslinf plugin, you can distribute it via NPM.

writing custom eslint rules

Wriiting it to work, you still need to install it as a node package though. Engineers at Flexport are opinionated about the code we write. Custom EsLint rules come in handy on a project-level basis. On top of that we have the EsLint plugin for VsCode, which looks like this in the editor:.

Working with Rules – ESLint – Pluggable JavaScript linter

The above methods return a fixing object. The third and often overlooked set of testing is continuity testing, also known as static code analysis.


In statically compiled languages, we usually lean on the compiler to catch out common errors or plain stupidities. If you make a fix function which returns multiple fixing objects, those fixing objects must not be overlapped.

Writing custom EsLint rules

It should only have the configuration that is necessary for ESLint to understand your codebase such as globals and parserOptions. The yeoman rule generator will give us a few new files:. One danger of having a bunch of custom eslint rules is that you may be papering over weak abstractions in your codebase.

First we need to know what part of the static tree we are going to lint. That becomes a problem both for new hires, which have to take more time to ramp up, and for current dev switching jobs as they’ll have a hard time abandoning what they learned. You are commenting using your Twitter account.

writing custom eslint rules

Try adding a simple template literal in your code. Fill in your details below or click an icon to log in: This method accepts a single argument, which is an object containing the following properties:. Ideally, we want the following:.

To keep the linting process efficient and unobtrusive, it is useful to writig the performance impact of new rules or modifications to existing rules.