Linting TypeScript Vue.js Components with Wotan

TypeScript is a special language. People tend to either love it or vehemently hate it (though it seems like most of those who’ve tried it, love it). Regardless of your opinion, TypeScript can be quite convenient at times. But, it can be a pain to get it working properly with Vue. Since TypeScript uses its own linting and compiling tools, integrating it into an existing toolchain can be quite an exploration of arcane arts. Getting TypeScript to lint, for example, Vue Single File Components, cannot be directly done by tslint. You have to go through some convoluted code transforms and such to be able to get something remotely workable. But what if there was another way? Enter wotan, a pluggable TypeScript and JavaScript linter. It has plugins for Vue Single File Components and can bolt right on to your existing tslint project.

Let’s take a look at how we can get Vue Single File Components linted using wotan.

This tutorial assumes you’ve got a project already set up with TypeScript. Something along the lines of Microsoft’s official TypeScript-Vue Starter Project

Install Wotan and Related Plugins

We’re going to need three packages:

1. The wotan CLI. Does the usual things that CLIs do.
2. Vé - A preprocessor for Wotan that extracts scripts from Vue Single File Components for linting.
3. Valtýr - A plugin for Wotan that effectively works as a drop-in replacement for tslint. It can use your tslint.json files unchanged.

$ npm install --save-dev @fimbul/wotan @fimbul/ve @fimbul/valtyr

Configure Wotan

Create a new file called .fimbullinter.yaml. This holds the configuration that tells wotan how to lint your project.

# Tell wotan to use the valtyr module for linting.
modules: "@fimbul/valtyr"
# Valtýr configuration.
valtyr:
  overrides:
    # Use the Vé preprocessor for all *.vue files.
    # Valtýr will still run for *.ts files by default.
    - files: "*.vue"
      processor: "@fimbul/ve"

Lint!

Now, you can lint your project simply by running wotan in the project directory.

For example, here’s the output I get when running wotan on the default TypeScript-Vue Starter Project.

Yikes!

Thankfully, all of those errors can be automatically fixed using wotan --fix.

Don’t like the linter configuration? Just configure tslint.json like you would with any other TypeScript project!

Take a look at Wotan and Valtýr’s many options to get a feel for what they can do.

And with that, you should be good to go!