mpx-eslint-parser

mpx-eslint-parser

The ESLint custom parser for .mpx files.

⤴️ Motivation

This parser allows us to lint the <template> of .mpx files. We can make mistakes easily on <template> if we use complex directives and expressions in the template. This parser and the rules of eslint-plugin-mpx would catch some of the mistakes.

💿 Installation

$ npm install --save-dev eslint mpx-eslint-parser

• Requires Node.js 6.5.0 or later.
• Requires ESLint 5.0.0 or later.
• Requires babel-eslint 8.1.1 or later if you want it. (optional)
• Requires @typescript-eslint/parser 1.0.0 or later if you want it. (optional)

📖 Usage

1. Write parser option into your .eslintrc.* file.
2. Use glob patterns or --ext .mpx CLI option.

{
    "extends": "eslint:recommended",
    "parser": "mpx-eslint-parser"
}

$ eslint "src/**/*.{js,mpx}"
# or
$ eslint src --ext .mpx

🔧 Options

parserOptions has the same properties as what espree, the default parser of ESLint, is supporting. For example:

{
    "parser": "mpx-eslint-parser",
    "parserOptions": {
        "sourceType": "module",
        "ecmaVersion": 2018,
        "ecmaFeatures": {
            "globalReturn": false,
            "impliedStrict": false,
            "jsx": false
        }
    }
}

parserOptions.parser

You can use parserOptions.parser property to specify a custom parser to parse <script> tags. Other properties than parser would be given to the specified parser. For example:

{
    "parser": "mpx-eslint-parser",
    "parserOptions": {
        "parser": "babel-eslint",
        "sourceType": "module",
        "allowImportExportEverywhere": false
    }
}

{
    "parser": "mpx-eslint-parser",
    "parserOptions": {
        "parser": "@typescript-eslint/parser"
    }
}

If the parserOptions.parser is false, the mpx-eslint-parser skips parsing <script> tags completely. This is useful for people who use the language ESLint community doesn't provide custom parser implementation.

🎇 Usage for custom rules / plugins

• This parser provides parserServices to traverse <template>.
  • defineTemplateBodyVisitor(templateVisitor, scriptVisitor) ... returns ESLint visitor to traverse <template>.
  • getTemplateBodyTokenStore() ... returns ESLint TokenStore to get the tokens of <template>.
  • getDocumentFragment() ... returns the root VDocumentFragment.
• ast.md is <template> AST specification.
• mustache-interpolation-spacing.js is an example.

⚠️ Known Limitations

Some rules make warnings due to the outside of <script> tags. Please disable those rules for .mpx files as necessary.

• eol-last
• linebreak-style
• max-len
• max-lines
• no-trailing-spaces
• unicode-bom
• Other rules which are using the source code text instead of AST might be confused as well.

📰 Changelog

• GitHub Releases

🍻 Contributing

Welcome contributing!

Please use GitHub's Issues/PRs.

If you want to write code, please execute npm install && npm run setup after you cloned this repository. The npm install command installs dependencies. The npm run setup command initializes ESLint as git submodules for tests.

Development Tools

• npm test runs tests and measures coverage.
• npm run build compiles TypeScript source code to index.js, index.js.map, and index.d.ts.
• npm run coverage shows the coverage result of npm test command with the default browser.
• npm run clean removes the temporary files which are created by npm test and npm run build.
• npm run lint runs ESLint.
• npm run setup setups submodules to develop.
• npm run update-fixtures updates files in test/fixtures/ast directory based on test/fixtures/ast/*/source.mpx files.
• npm run watch runs build, update-fixtures, and tests with --watch option.