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1/**
2 * @fileoverview Rule to enforce the position of line comments
3 * @author Alberto Rodríguez
4 */
5"use strict";
6
7const astUtils = require("./utils/ast-utils");
8
9//------------------------------------------------------------------------------
10// Rule Definition
11//------------------------------------------------------------------------------
12
13module.exports = {
14    meta: {
15        type: "layout",
16
17        docs: {
18            description: "enforce position of line comments",
19            category: "Stylistic Issues",
20            recommended: false,
21            url: "https://eslint.org/docs/rules/line-comment-position"
22        },
23
24        schema: [
25            {
26                oneOf: [
27                    {
28                        enum: ["above", "beside"]
29                    },
30                    {
31                        type: "object",
32                        properties: {
33                            position: {
34                                enum: ["above", "beside"]
35                            },
36                            ignorePattern: {
37                                type: "string"
38                            },
39                            applyDefaultPatterns: {
40                                type: "boolean"
41                            },
42                            applyDefaultIgnorePatterns: {
43                                type: "boolean"
44                            }
45                        },
46                        additionalProperties: false
47                    }
48                ]
49            }
50        ],
51        messages: {
52            above: "Expected comment to be above code.",
53            beside: "Expected comment to be beside code."
54        }
55    },
56
57    create(context) {
58        const options = context.options[0];
59
60        let above,
61            ignorePattern,
62            applyDefaultIgnorePatterns = true;
63
64        if (!options || typeof options === "string") {
65            above = !options || options === "above";
66
67        } else {
68            above = !options.position || options.position === "above";
69            ignorePattern = options.ignorePattern;
70
71            if (Object.prototype.hasOwnProperty.call(options, "applyDefaultIgnorePatterns")) {
72                applyDefaultIgnorePatterns = options.applyDefaultIgnorePatterns;
73            } else {
74                applyDefaultIgnorePatterns = options.applyDefaultPatterns !== false;
75            }
76        }
77
78        const defaultIgnoreRegExp = astUtils.COMMENTS_IGNORE_PATTERN;
79        const fallThroughRegExp = /^\s*falls?\s?through/u;
80        const customIgnoreRegExp = new RegExp(ignorePattern, "u");
81        const sourceCode = context.getSourceCode();
82
83        //--------------------------------------------------------------------------
84        // Public
85        //--------------------------------------------------------------------------
86
87        return {
88            Program() {
89                const comments = sourceCode.getAllComments();
90
91                comments.filter(token => token.type === "Line").forEach(node => {
92                    if (applyDefaultIgnorePatterns && (defaultIgnoreRegExp.test(node.value) || fallThroughRegExp.test(node.value))) {
93                        return;
94                    }
95
96                    if (ignorePattern && customIgnoreRegExp.test(node.value)) {
97                        return;
98                    }
99
100                    const previous = sourceCode.getTokenBefore(node, { includeComments: true });
101                    const isOnSameLine = previous && previous.loc.end.line === node.loc.start.line;
102
103                    if (above) {
104                        if (isOnSameLine) {
105                            context.report({
106                                node,
107                                messageId: "above"
108                            });
109                        }
110                    } else {
111                        if (!isOnSameLine) {
112                            context.report({
113                                node,
114                                messageId: "beside"
115                            });
116                        }
117                    }
118                });
119            }
120        };
121    }
122};
123