codtracker-js/node_modules/eslint/lib/rules/arrow-parens.js

/**
 * @fileoverview Rule to require parens in arrow function arguments.
 * @author Jxck
 * @deprecated in ESLint v8.53.0
 */
'use strict';

//------------------------------------------------------------------------------
// Requirements
//------------------------------------------------------------------------------

const astUtils = require('./utils/ast-utils');

//------------------------------------------------------------------------------
// Helpers
//------------------------------------------------------------------------------

/**
 * Determines if the given arrow function has block body.
 * @param {ASTNode} node `ArrowFunctionExpression` node.
 * @returns {boolean} `true` if the function has block body.
 */
function hasBlockBody(node) {
  return node.body.type === 'BlockStatement';
}

//------------------------------------------------------------------------------
// Rule Definition
//------------------------------------------------------------------------------

/** @type {import('../types').Rule.RuleModule} */
module.exports = {
  meta: {
    deprecated: {
      message: 'Formatting rules are being moved out of ESLint core.',
      url: 'https://eslint.org/blog/2023/10/deprecating-formatting-rules/',
      deprecatedSince: '8.53.0',
      availableUntil: '10.0.0',
      replacedBy: [
        {
          message:
            'ESLint Stylistic now maintains deprecated stylistic core rules.',
          url: 'https://eslint.style/guide/migration',
          plugin: {
            name: '@stylistic/eslint-plugin-js',
            url: 'https://eslint.style/packages/js',
          },
          rule: {
            name: 'arrow-parens',
            url: 'https://eslint.style/rules/js/arrow-parens',
          },
        },
      ],
    },
    type: 'layout',

    docs: {
      description: 'Require parentheses around arrow function arguments',
      recommended: false,
      url: 'https://eslint.org/docs/latest/rules/arrow-parens',
    },

    fixable: 'code',

    schema: [
      {
        enum: ['always', 'as-needed'],
      },
      {
        type: 'object',
        properties: {
          requireForBlockBody: {
            type: 'boolean',
            default: false,
          },
        },
        additionalProperties: false,
      },
    ],

    messages: {
      unexpectedParens:
        'Unexpected parentheses around single function argument.',
      expectedParens: 'Expected parentheses around arrow function argument.',

      unexpectedParensInline:
        'Unexpected parentheses around single function argument having a body with no curly braces.',
      expectedParensBlock:
        'Expected parentheses around arrow function argument having a body with curly braces.',
    },
  },

  create(context) {
    const asNeeded = context.options[0] === 'as-needed';
    const requireForBlockBody =
      asNeeded &&
      context.options[1] &&
      context.options[1].requireForBlockBody === true;

    const sourceCode = context.sourceCode;

    /**
     * Finds opening paren of parameters for the given arrow function, if it exists.
     * It is assumed that the given arrow function has exactly one parameter.
     * @param {ASTNode} node `ArrowFunctionExpression` node.
     * @returns {Token|null} the opening paren, or `null` if the given arrow function doesn't have parens of parameters.
     */
    function findOpeningParenOfParams(node) {
      const tokenBeforeParams = sourceCode.getTokenBefore(node.params[0]);

      if (
        tokenBeforeParams &&
        astUtils.isOpeningParenToken(tokenBeforeParams) &&
        node.range[0] <= tokenBeforeParams.range[0]
      ) {
        return tokenBeforeParams;
      }

      return null;
    }

    /**
     * Finds closing paren of parameters for the given arrow function.
     * It is assumed that the given arrow function has parens of parameters and that it has exactly one parameter.
     * @param {ASTNode} node `ArrowFunctionExpression` node.
     * @returns {Token} the closing paren of parameters.
     */
    function getClosingParenOfParams(node) {
      return sourceCode.getTokenAfter(
        node.params[0],
        astUtils.isClosingParenToken
      );
    }

    /**
     * Determines whether the given arrow function has comments inside parens of parameters.
     * It is assumed that the given arrow function has parens of parameters.
     * @param {ASTNode} node `ArrowFunctionExpression` node.
     * @param {Token} openingParen Opening paren of parameters.
     * @returns {boolean} `true` if the function has at least one comment inside of parens of parameters.
     */
    function hasCommentsInParensOfParams(node, openingParen) {
      return sourceCode.commentsExistBetween(
        openingParen,
        getClosingParenOfParams(node)
      );
    }

    /**
     * Determines whether the given arrow function has unexpected tokens before opening paren of parameters,
     * in which case it will be assumed that the existing parens of parameters are necessary.
     * Only tokens within the range of the arrow function (tokens that are part of the arrow function) are taken into account.
     * Example: <T>(a) => b
     * @param {ASTNode} node `ArrowFunctionExpression` node.
     * @param {Token} openingParen Opening paren of parameters.
     * @returns {boolean} `true` if the function has at least one unexpected token.
     */
    function hasUnexpectedTokensBeforeOpeningParen(node, openingParen) {
      const expectedCount = node.async ? 1 : 0;

      return (
        sourceCode.getFirstToken(node, { skip: expectedCount }) !== openingParen
      );
    }

    return {
      'ArrowFunctionExpression[params.length=1]'(node) {
        const shouldHaveParens =
          !asNeeded || (requireForBlockBody && hasBlockBody(node));
        const openingParen = findOpeningParenOfParams(node);
        const hasParens = openingParen !== null;
        const [param] = node.params;

        if (shouldHaveParens && !hasParens) {
          context.report({
            node,
            messageId:
              requireForBlockBody ? 'expectedParensBlock' : 'expectedParens',
            loc: param.loc,
            *fix(fixer) {
              yield fixer.insertTextBefore(param, '(');
              yield fixer.insertTextAfter(param, ')');
            },
          });
        }

        if (
          !shouldHaveParens &&
          hasParens &&
          param.type === 'Identifier' &&
          !param.typeAnnotation &&
          !node.returnType &&
          !hasCommentsInParensOfParams(node, openingParen) &&
          !hasUnexpectedTokensBeforeOpeningParen(node, openingParen)
        ) {
          context.report({
            node,
            messageId:
              requireForBlockBody ?
                'unexpectedParensInline'
              : 'unexpectedParens',
            loc: param.loc,
            *fix(fixer) {
              const tokenBeforeOpeningParen =
                sourceCode.getTokenBefore(openingParen);
              const closingParen = getClosingParenOfParams(node);

              if (
                tokenBeforeOpeningParen &&
                tokenBeforeOpeningParen.range[1] === openingParen.range[0] &&
                !astUtils.canTokensBeAdjacent(
                  tokenBeforeOpeningParen,
                  sourceCode.getFirstToken(param)
                )
              ) {
                yield fixer.insertTextBefore(openingParen, ' ');
              }

              // remove parens, whitespace inside parens, and possible trailing comma
              yield fixer.removeRange([openingParen.range[0], param.range[0]]);
              yield fixer.removeRange([param.range[1], closingParen.range[1]]);
            },
          });
        }
      },
    };
  },
};