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1/**
2 * @fileoverview A rule to set the maximum depth block can be nested in a function.
3 * @author Ian Christian Myers
4 */
5
6"use strict";
7
8//------------------------------------------------------------------------------
9// Rule Definition
10//------------------------------------------------------------------------------
11
12module.exports = {
13    meta: {
14        type: "suggestion",
15
16        docs: {
17            description: "enforce a maximum depth that blocks can be nested",
18            category: "Stylistic Issues",
19            recommended: false,
20            url: "https://eslint.org/docs/rules/max-depth"
21        },
22
23        schema: [
24            {
25                oneOf: [
26                    {
27                        type: "integer",
28                        minimum: 0
29                    },
30                    {
31                        type: "object",
32                        properties: {
33                            maximum: {
34                                type: "integer",
35                                minimum: 0
36                            },
37                            max: {
38                                type: "integer",
39                                minimum: 0
40                            }
41                        },
42                        additionalProperties: false
43                    }
44                ]
45            }
46        ],
47        messages: {
48            tooDeeply: "Blocks are nested too deeply ({{depth}}). Maximum allowed is {{maxDepth}}."
49        }
50    },
51
52    create(context) {
53
54        //--------------------------------------------------------------------------
55        // Helpers
56        //--------------------------------------------------------------------------
57
58        const functionStack = [],
59            option = context.options[0];
60        let maxDepth = 4;
61
62        if (
63            typeof option === "object" &&
64            (Object.prototype.hasOwnProperty.call(option, "maximum") || Object.prototype.hasOwnProperty.call(option, "max"))
65        ) {
66            maxDepth = option.maximum || option.max;
67        }
68        if (typeof option === "number") {
69            maxDepth = option;
70        }
71
72        /**
73         * When parsing a new function, store it in our function stack
74         * @returns {void}
75         * @private
76         */
77        function startFunction() {
78            functionStack.push(0);
79        }
80
81        /**
82         * When parsing is done then pop out the reference
83         * @returns {void}
84         * @private
85         */
86        function endFunction() {
87            functionStack.pop();
88        }
89
90        /**
91         * Save the block and Evaluate the node
92         * @param {ASTNode} node node to evaluate
93         * @returns {void}
94         * @private
95         */
96        function pushBlock(node) {
97            const len = ++functionStack[functionStack.length - 1];
98
99            if (len > maxDepth) {
100                context.report({ node, messageId: "tooDeeply", data: { depth: len, maxDepth } });
101            }
102        }
103
104        /**
105         * Pop the saved block
106         * @returns {void}
107         * @private
108         */
109        function popBlock() {
110            functionStack[functionStack.length - 1]--;
111        }
112
113        //--------------------------------------------------------------------------
114        // Public API
115        //--------------------------------------------------------------------------
116
117        return {
118            Program: startFunction,
119            FunctionDeclaration: startFunction,
120            FunctionExpression: startFunction,
121            ArrowFunctionExpression: startFunction,
122
123            IfStatement(node) {
124                if (node.parent.type !== "IfStatement") {
125                    pushBlock(node);
126                }
127            },
128            SwitchStatement: pushBlock,
129            TryStatement: pushBlock,
130            DoWhileStatement: pushBlock,
131            WhileStatement: pushBlock,
132            WithStatement: pushBlock,
133            ForStatement: pushBlock,
134            ForInStatement: pushBlock,
135            ForOfStatement: pushBlock,
136
137            "IfStatement:exit": popBlock,
138            "SwitchStatement:exit": popBlock,
139            "TryStatement:exit": popBlock,
140            "DoWhileStatement:exit": popBlock,
141            "WhileStatement:exit": popBlock,
142            "WithStatement:exit": popBlock,
143            "ForStatement:exit": popBlock,
144            "ForInStatement:exit": popBlock,
145            "ForOfStatement:exit": popBlock,
146
147            "FunctionDeclaration:exit": endFunction,
148            "FunctionExpression:exit": endFunction,
149            "ArrowFunctionExpression:exit": endFunction,
150            "Program:exit": endFunction
151        };
152
153    }
154};
155