yaml-lint

What is yaml-lint?

The 'yaml-lint' npm package is a tool for validating YAML files. It checks for syntax errors and ensures that the YAML content is properly formatted. This is particularly useful for developers who work with YAML configuration files and need to ensure their correctness.

What are yaml-lint's main functionalities?

Linting YAML files

This feature allows you to lint a YAML string to check for syntax errors. If the YAML content is valid, it will log 'YAML is valid'. If there are any errors, it will catch them and log 'YAML is invalid' along with the error details.

const yamlLint = require('yaml-lint');

const yamlContent = `
foo: bar
baz: qux
`;

yamlLint.lint(yamlContent)
  .then(() => {
    console.log('YAML is valid');
  })
  .catch((error) => {
    console.error('YAML is invalid:', error);
  });

Linting YAML files from the filesystem

This feature allows you to lint a YAML file from the filesystem. It reads the file content and checks for syntax errors. If the file is valid, it will log 'YAML file is valid'. If there are any errors, it will catch them and log 'YAML file is invalid' along with the error details.

const yamlLint = require('yaml-lint');
const fs = require('fs');

const yamlFilePath = 'path/to/your/file.yaml';

fs.readFile(yamlFilePath, 'utf8', (err, data) => {
  if (err) throw err;

  yamlLint.lint(data)
    .then(() => {
      console.log('YAML file is valid');
    })
    .catch((error) => {
      console.error('YAML file is invalid:', error);
    });
});

Other packages similar to yaml-lint

js-yaml

The 'js-yaml' package is a YAML parser and dumper for JavaScript. It can parse YAML strings into JavaScript objects and serialize JavaScript objects into YAML strings. Unlike 'yaml-lint', 'js-yaml' focuses more on parsing and serializing YAML rather than just linting.

yaml

The 'yaml' package is another YAML parser and stringifier for JavaScript. It provides a comprehensive set of features for working with YAML, including parsing, stringifying, and schema validation. It offers more advanced features compared to 'yaml-lint', which is primarily focused on linting.

yaml-js

The 'yaml-js' package is a pure JavaScript YAML parser and serializer. It provides basic functionality for parsing and serializing YAML, similar to 'js-yaml' and 'yaml'. It is less focused on linting and more on general YAML manipulation.

README

YAML Lint

A simple (CLI) tool to lint YAML files

Usage

npm install --save-dev yaml-lint

const yamlLint = require('yaml-lint');

yamlLint
  .lint('test: 123')
  .then(() => {
    console.log('Valid YAML file.');
  })
  .catch((error) => {
    console.error('Invalid YAML file.', error);
  });

CLI

npm install -g yaml-lint

yamllint test.yaml

Options

YAML Lint is configured using the following options via a configuration file, environment variables, and/or command-line arguments.

First of all, YAML Lint looks for a JSON file called .yaml-lint.json within the current working directory.

{
  "schema": "CORE_SCHEMA",
  "ignore": "dir/*.yaml"
}

Afterwards, YAML Lint will take environment variables into account.

YAMLLINT_SCHEMA=CORE_SCHEMA YAMLLINT_IGNORE=dir/*.yaml yamllint

Concluding, YAML Lint will take command-line arguments into account.

yamllint --schema=CORE_SCHEMA --ignore=dir/*.yaml

(All options are merged into a single configuration using the hierarchy described above.)

schema (string)

Specifies a schema to use

• DEFAULT_SCHEMA All supported YAML types
• FAILSAFE_SCHEMA Only strings, arrays, and plain objects (http://www.yaml.org/spec/1.2/spec.html#id2802346)
• JSON_SCHEMA All JSON-supported types (http://www.yaml.org/spec/1.2/spec.html#id2803231)
• CORE_SCHEMA Same as JSON_SCHEMA (http://www.yaml.org/spec/1.2/spec.html#id2804923)

ignore (string or array of strings)

Specifies one or multiple glob patterns to ignore

yamllint **/*.(yaml|yml) --ignore=foobar.yml --ignore=dir/*.yaml

Changelog

• 1.7.0
  • Fix glob pattern to enforce forward slashes to prevent Windows issues
  • Run tests on different operating systems in CI
• 1.6.0
  • Implement support for multi-document sources
• 1.5.0
  • Add tests for CLI
• 1.4.0
  • Display all failing files instead of only the first best one
• 1.3.0
  • Migrate to TypeScript and update dependencies
• 1.2.4
  • Fix paths for ignored patterns
• 1.2.3
  • Remove nocase rule to prevent problems on Windows
• 1.2.2
  • Fix CLI support relative paths
• 1.2.1
  • Fix README
• 1.2.0
  • Add documentation regarding how to specify options
  • Update dependencies
  • Support ignoring specific files
• 1.1.0
  • Update dependencies
  • Migrate syntax to ES2015+
• 1.0.0
  • Update dependencies
  • Enable tests for Node.js 8
  • Remove support for Node.js 0.x
• 0.0.4
  • Print file names when logging YAML errors while using the CLI
• 0.0.3
  • Implement check for empty file selections while using the CLI
• 0.0.2
  • Prettier error messages within CLI
  • Add shebang for CLI
• 0.0.1
  • Initial version

License

Copyright (c) 2022 Thomas Rasshofer
Licensed under the MIT license.

See LICENSE for more info.

Contributors

• @rasshofer
• @sapegin
• @bendrucker
• @PeterDaveHello
• @poppinlp
• @AndersDJohnson