codtracker-js/node_modules/eslint/lib/rules/no-console.js

/**
 * @fileoverview Rule to flag use of console object
 * @author Nicholas C. Zakas
 */

'use strict';

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

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

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

/** @type {import('../types').Rule.RuleModule} */
module.exports = {
  meta: {
    type: 'suggestion',

    defaultOptions: [{}],

    docs: {
      description: 'Disallow the use of `console`',
      recommended: false,
      url: 'https://eslint.org/docs/latest/rules/no-console',
    },

    schema: [
      {
        type: 'object',
        properties: {
          allow: {
            type: 'array',
            items: {
              type: 'string',
            },
            minItems: 1,
            uniqueItems: true,
          },
        },
        additionalProperties: false,
      },
    ],

    hasSuggestions: true,

    messages: {
      unexpected: 'Unexpected console statement.',
      limited:
        'Unexpected console statement. Only these console methods are allowed: {{ allowed }}.',
      removeConsole: 'Remove the console.{{ propertyName }}().',
      removeMethodCall: 'Remove the console method call.',
    },
  },

  create(context) {
    const [{ allow: allowed = [] }] = context.options;
    const sourceCode = context.sourceCode;

    /**
     * Checks whether the given reference is 'console' or not.
     * @param {eslint-scope.Reference} reference The reference to check.
     * @returns {boolean} `true` if the reference is 'console'.
     */
    function isConsole(reference) {
      const id = reference.identifier;

      return id && id.name === 'console';
    }

    /**
     * Checks whether the property name of the given MemberExpression node
     * is allowed by options or not.
     * @param {ASTNode} node The MemberExpression node to check.
     * @returns {boolean} `true` if the property name of the node is allowed.
     */
    function isAllowed(node) {
      const propertyName = astUtils.getStaticPropertyName(node);

      return propertyName && allowed.includes(propertyName);
    }

    /**
     * Checks whether the given reference is a member access which is not
     * allowed by options or not.
     * @param {eslint-scope.Reference} reference The reference to check.
     * @returns {boolean} `true` if the reference is a member access which
     *      is not allowed by options.
     */
    function isMemberAccessExceptAllowed(reference) {
      const node = reference.identifier;
      const parent = node.parent;

      return (
        parent.type === 'MemberExpression' &&
        parent.object === node &&
        !isAllowed(parent)
      );
    }

    /**
     * Checks if removing the ExpressionStatement node will cause ASI to
     * break.
     * eg.
     * foo()
     * console.log();
     * [1, 2, 3].forEach(a => doSomething(a))
     *
     * Removing the console.log(); statement should leave two statements, but
     * here the two statements will become one because [ causes continuation after
     * foo().
     * @param {ASTNode} node The ExpressionStatement node to check.
     * @returns {boolean} `true` if ASI will break after removing the ExpressionStatement
     *      node.
     */
    function maybeAsiHazard(node) {
      const SAFE_TOKENS_BEFORE = /^[:;{]$/u; // One of :;{
      const UNSAFE_CHARS_AFTER = /^[-[(/+`]/u; // One of [(/+-`

      const tokenBefore = sourceCode.getTokenBefore(node);
      const tokenAfter = sourceCode.getTokenAfter(node);

      return (
        Boolean(tokenAfter) &&
        UNSAFE_CHARS_AFTER.test(tokenAfter.value) &&
        tokenAfter.value !== '++' &&
        tokenAfter.value !== '--' &&
        Boolean(tokenBefore) &&
        !SAFE_TOKENS_BEFORE.test(tokenBefore.value)
      );
    }

    /**
     * Checks if the MemberExpression node's parent.parent.parent is a
     * Program, BlockStatement, StaticBlock, or SwitchCase node. This check
     * is necessary to avoid providing a suggestion that might cause a syntax error.
     *
     * eg. if (a) console.log(b), removing console.log() here will lead to a
     *     syntax error.
     *     if (a) { console.log(b) }, removing console.log() here is acceptable.
     *
     * Additionally, it checks if the callee of the CallExpression node is
     * the node itself.
     *
     * eg. foo(console.log), cannot provide a suggestion here.
     * @param {ASTNode} node The MemberExpression node to check.
     * @returns {boolean} `true` if a suggestion can be provided for a node.
     */
    function canProvideSuggestions(node) {
      return (
        node.parent.type === 'CallExpression' &&
        node.parent.callee === node &&
        node.parent.parent.type === 'ExpressionStatement' &&
        astUtils.STATEMENT_LIST_PARENTS.has(node.parent.parent.parent.type) &&
        !maybeAsiHazard(node.parent.parent)
      );
    }

    /**
     * Reports the given reference as a violation.
     * @param {eslint-scope.Reference} reference The reference to report.
     * @returns {void}
     */
    function report(reference) {
      const node = reference.identifier.parent;

      const suggest = [];

      if (canProvideSuggestions(node)) {
        const suggestion = {
          fix(fixer) {
            return fixer.remove(node.parent.parent);
          },
        };

        if (node.computed) {
          suggestion.messageId = 'removeMethodCall';
        } else {
          suggestion.messageId = 'removeConsole';
          suggestion.data = { propertyName: node.property.name };
        }
        suggest.push(suggestion);
      }
      context.report({
        node,
        loc: node.loc,
        messageId: allowed.length ? 'limited' : 'unexpected',
        data: { allowed: allowed.join(', ') },
        suggest,
      });
    }

    return {
      'Program:exit'(node) {
        const scope = sourceCode.getScope(node);
        const consoleVar = astUtils.getVariableByName(scope, 'console');
        const shadowed = consoleVar && consoleVar.defs.length > 0;

        /*
         * 'scope.through' includes all references to undefined
         * variables. If the variable 'console' is not defined, it uses
         * 'scope.through'.
         */
        const references =
          consoleVar ? consoleVar.references : scope.through.filter(isConsole);

        if (!shadowed) {
          references.filter(isMemberAccessExceptAllowed).forEach(report);
        }
      },
    };
  },
};