About

Flint’s YML plugin supports linting .yaml/.yml source code. It comes provided with the flint npm package.

Presets

Flint’s YML plugin provides the following presets:

Preset	Recommended	Description
logical	✅ Always	Common rules for finding bugs and enforcing good logical practices in YML files.
logicalStrict	☑️ When Ready	Additional rules for finding bugs and enforcing good logical practices in YML files.
stylistic	✅ Always	Common rules for consistent styling and best stylistic practices in YML files.
stylisticStrict	☑️ When Ready	Additional rules for consistent styling and best stylistic practices in YML files.

If you are just getting started with linting, Flint recommends using the logical and stylistic presets:

flint.config.ts

import { defineConfig, yml } from "flint";

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

If you are experienced with both YML and linting, Flint recommends using the logicalStrict and stylisticStrict presets:

flint.config.ts

import { defineConfig, yml } from "flint";

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

Note

Coming soon: more expansive documentation on choosing and combining plugins & presets with Flint.

logical

Rules that find bugs and enforce good YML practices for most-to-all YML files.

flint.config.ts

import { defineConfig, yml } from "flint";

export default defineConfig({
  use: [
    {
      files: yml.files.all,
      rules: yml.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 YML and using a linter.

flint.config.ts

import { defineConfig, yml } from "flint";

export default defineConfig({
  use: [
    {
      files: yml.files.all,
      rules: yml.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 YML files.

flint.config.ts

import { defineConfig, yml } from "flint";

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

stylisticStrict

Additional stylistic 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 YML and using a linter.

flint.config.ts

import { defineConfig, yml } from "flint";

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

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

Rules

Implemented: 1 of 11 (9%)

Flint Name	Preset	Biome Rule(s)	Deno Lint Rule(s)	ESLint Rule(s)	Oxlint Rule(s)
emptyDocuments	Logical			yml/no-empty-document
emptyMappingKeys	Logical			yml/no-empty-key
emptyMappingValues	Logical			yml/no-empty-mapping-value
emptySequenceEntries	Logical			yml/no-empty-sequence-entry
stringMappingKeys	Logical (Strict)			yml/require-string-key
blockMappings	Stylistic			yml/block-mapping
blockSequences	Stylistic			yml/block-sequence
irregularWhitespace	Stylistic			yml/no-irregular-whitespace
fileExtensions	Stylistic (Strict)			yml/file-extension
numericTrailingZeros	Stylistic (Strict)			yml/no-trailing-zeros
plainScalars	Stylistic (Strict)			yml/plain-scalar

Selectors

Flint’s YAML plugin provides the following file selector:

• all: **/*.{yaml,yml}