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⚡ Performance tips

Depending on the device you are operating on, in-editor performance can be a concern with Sheriff.
typescript-eslint can be particularly taxing on the system, so some performance considerations are in order.

Rules performance benchmarking​

The slowest rules in Sheriff are the ones that require type information to work.
typescript-eslint maintains a list of type-aware rules, which can help track them down.

You can benchmark rule performance by running the following in a terminal:

TIMING=1 npx eslint

Learn more on the official ESLint docs page on profiling rule performance.

warning

If typed linting is enabled, the first typescript-eslint rule to run will look a lot slower, when, in reality, all typescript-eslint rules are at minimum as slow as a tsc run, but the output is cached. For more information, see Slow ESLint Rules § Performance | typescript-eslint.

Rule performance optimization strategies​

You can leverage a few different techniques to improve slow linting time.
You can choose one technique to employ or mix-and-match them.

Disable some of the heaviest rules​

After profiling rules, you can assess which of the slowest rules you can live without and disable them.

Enable some of the heaviest rules only on CI​

This approach has a little more overhead, but you could try to run the heaviest rules only on CI.

Here is an example of how to achieve this:

eslint.config.js
import sheriff from "eslint-config-sheriff";
import { defineFlatConfig } from "eslint-define-config";

const sheriffOptions = {
  react: false,
  next: false,
  astro: false,
  lodash: false,
  remeda: false,
  playwright: false,
  jest: false,
  vitest: false,
};

export default defineFlatConfig([
  ...sheriff(sheriffOptions),
  {
    rules: {
      "@typescript-eslint/no-misused-promises": process.env.CI ? 2 : 0,
    },
  },
]);

There is a tradeoff here, as this approach is a DX degradation that can lead to developer frustration, because code that is perfectly valid local environment could still fail in CI.

You may find typescript-eslint’s disableTypeChecked config useful in these scenarios.

Review glob patterns​

ESLint, TypeScript and Sheriff use minimatch syntax to handle glob patterns.
Wide glob patterns (in particular, the usage of globstars1) can lead to performance degradations.

Pay special attention to:

Footnotes​

  1. A globstar is a ** pattern. ↩