Flint Plugin

Rules for writing third-party Flint plugins and custom rules. Meta!
This plugin is provided in a standalone @flint.fyi/plugin-flint npm package.

npm

npm install @flint.fyi/plugin-flint

bun

bun install @flint.fyi/plugin-flint

deno

deno install @flint.fyi/plugin-flint

pnpm

pnpm install @flint.fyi/plugin-flint

yarn

yarn install @flint.fyi/plugin-flint

Presets

logical

Rules that find bugs and enforce good practices for Flint plugins and rules.

flint.config.ts

import { flint } from "@flint.fyi/plugin-flint";
import { defineConfig, ts } from "flint";

export default defineConfig({
  use: [
    {
      files: ts.files.all,
      rules: flint.presets.logical,
    },
  ],
});

logicalStrict

Additional logical rules that enforce best practices which are not always straightforward to implement. These rules are recommended for projects where a majority of developers are experienced with both JavaScript/TypeScript and writing plugins for a linter.

flint.config.ts

import { flint } from "@flint.fyi/plugin-flint";
import { defineConfig, ts } from "flint";

export default defineConfig({
  use: [
    {
      files: ts.files.all,
      rules: flint.presets.logicalStrict,
    },
  ],
});

This preset’s rules are a superset of those in logical.

stylistic

Rules that enforce consistent styling and best stylistic practices for most-to-all Flint plugins.

flint.config.ts

import { flint } from "@flint.fyi/plugin-flint";
import { defineConfig, ts } from "flint";

export default defineConfig({
  use: [
    {
      files: ts.files.all,
      rules: flint.presets.stylistic,
    },
  ],
});

stylisticStrict

Additional stylistic rules that enforce best practices which are nice to keep consistent across Flint plugins. These rules are recommended for teams that want the stricter conventions enforced automatically.

flint.config.ts

import { flint } from "@flint.fyi/plugin-flint";
import { defineConfig, ts } from "flint";

export default defineConfig({
  use: [
    {
      files: ts.files.all,
      rules: flint.presets.stylisticStrict,
    },
  ],
});

This preset’s rules are a superset of those in stylistic.

Rules

Implemented: 10 of 16 (62.5%)

Flint Rule	Preset
invalidCodeLinesReports cases for invalid code that isn't formatted across lines.	logical
missingPlaceholdersReports context.report() calls missing data for message placeholders.	logical
nodePropertyInChecksDisallows using the in operator to check properties on TypeScript nodes.	logical
ruleCreationMethodsReports plugin rules created directly with language instead of through RuleCreator.	logical
ruleDescriptions	logical
rulePresets	logical
ruleURLs	logical
testCaseDuplicatesReports test cases that are identical to previous test cases.	logical
testCaseNameDuplicatesReports test cases that have the same name as a previous test case.	logical
testCaseNonStaticCodeTest case code should be a static string literal.	logical
testCaseOnlies	logical
unusedMessageIdsReports message IDs defined in the messages object that are never used in recognized report calls.	logical
unusedPlaceholders	logical
messagePhrases	logical (strict)
testShorthandsTest cases with only a code property can use string shorthand syntax instead of object literal syntax.	stylistic
pluginRuleOrderingReports Flint plugin rules arrays that are not sorted alphabetically.	stylistic (strict)