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1/**
2 * @fileoverview Rule to flag use of console object
3 * @author Nicholas C. Zakas
4 */
5
6"use strict";
7
8//------------------------------------------------------------------------------
9// Requirements
10//------------------------------------------------------------------------------
11
12const astUtils = require("./utils/ast-utils");
13
14//------------------------------------------------------------------------------
15// Rule Definition
16//------------------------------------------------------------------------------
17
18module.exports = {
19    meta: {
20        type: "suggestion",
21
22        docs: {
23            description: "disallow the use of `console`",
24            category: "Possible Errors",
25            recommended: false,
26            url: "https://eslint.org/docs/rules/no-console"
27        },
28
29        schema: [
30            {
31                type: "object",
32                properties: {
33                    allow: {
34                        type: "array",
35                        items: {
36                            type: "string"
37                        },
38                        minItems: 1,
39                        uniqueItems: true
40                    }
41                },
42                additionalProperties: false
43            }
44        ],
45
46        messages: {
47            unexpected: "Unexpected console statement."
48        }
49    },
50
51    create(context) {
52        const options = context.options[0] || {};
53        const allowed = options.allow || [];
54
55        /**
56         * Checks whether the given reference is 'console' or not.
57         * @param {eslint-scope.Reference} reference The reference to check.
58         * @returns {boolean} `true` if the reference is 'console'.
59         */
60        function isConsole(reference) {
61            const id = reference.identifier;
62
63            return id && id.name === "console";
64        }
65
66        /**
67         * Checks whether the property name of the given MemberExpression node
68         * is allowed by options or not.
69         * @param {ASTNode} node The MemberExpression node to check.
70         * @returns {boolean} `true` if the property name of the node is allowed.
71         */
72        function isAllowed(node) {
73            const propertyName = astUtils.getStaticPropertyName(node);
74
75            return propertyName && allowed.indexOf(propertyName) !== -1;
76        }
77
78        /**
79         * Checks whether the given reference is a member access which is not
80         * allowed by options or not.
81         * @param {eslint-scope.Reference} reference The reference to check.
82         * @returns {boolean} `true` if the reference is a member access which
83         *      is not allowed by options.
84         */
85        function isMemberAccessExceptAllowed(reference) {
86            const node = reference.identifier;
87            const parent = node.parent;
88
89            return (
90                parent.type === "MemberExpression" &&
91                parent.object === node &&
92                !isAllowed(parent)
93            );
94        }
95
96        /**
97         * Reports the given reference as a violation.
98         * @param {eslint-scope.Reference} reference The reference to report.
99         * @returns {void}
100         */
101        function report(reference) {
102            const node = reference.identifier.parent;
103
104            context.report({
105                node,
106                loc: node.loc,
107                messageId: "unexpected"
108            });
109        }
110
111        return {
112            "Program:exit"() {
113                const scope = context.getScope();
114                const consoleVar = astUtils.getVariableByName(scope, "console");
115                const shadowed = consoleVar && consoleVar.defs.length > 0;
116
117                /*
118                 * 'scope.through' includes all references to undefined
119                 * variables. If the variable 'console' is not defined, it uses
120                 * 'scope.through'.
121                 */
122                const references = consoleVar
123                    ? consoleVar.references
124                    : scope.through.filter(isConsole);
125
126                if (!shadowed) {
127                    references
128                        .filter(isMemberAccessExceptAllowed)
129                        .forEach(report);
130                }
131            }
132        };
133    }
134};
135