1 | /**
|
2 | * @fileoverview Rule to flag use of duplicate keys in an object.
|
3 | * @author Ian Christian Myers
|
4 | */
|
5 |
|
6 | ;
|
7 |
|
8 | //------------------------------------------------------------------------------
|
9 | // Requirements
|
10 | //------------------------------------------------------------------------------
|
11 |
|
12 | const astUtils = require("./utils/ast-utils");
|
13 |
|
14 | //------------------------------------------------------------------------------
|
15 | // Helpers
|
16 | //------------------------------------------------------------------------------
|
17 |
|
18 | const GET_KIND = /^(?:init|get)$/u;
|
19 | const SET_KIND = /^(?:init|set)$/u;
|
20 |
|
21 | /**
|
22 | * The class which stores properties' information of an object.
|
23 | */
|
24 | class ObjectInfo {
|
25 |
|
26 | // eslint-disable-next-line jsdoc/require-description
|
27 | /**
|
28 | * @param {ObjectInfo|null} upper The information of the outer object.
|
29 | * @param {ASTNode} node The ObjectExpression node of this information.
|
30 | */
|
31 | constructor(upper, node) {
|
32 | this.upper = upper;
|
33 | this.node = node;
|
34 | this.properties = new Map();
|
35 | }
|
36 |
|
37 | /**
|
38 | * Gets the information of the given Property node.
|
39 | * @param {ASTNode} node The Property node to get.
|
40 | * @returns {{get: boolean, set: boolean}} The information of the property.
|
41 | */
|
42 | getPropertyInfo(node) {
|
43 | const name = astUtils.getStaticPropertyName(node);
|
44 |
|
45 | if (!this.properties.has(name)) {
|
46 | this.properties.set(name, { get: false, set: false });
|
47 | }
|
48 | return this.properties.get(name);
|
49 | }
|
50 |
|
51 | /**
|
52 | * Checks whether the given property has been defined already or not.
|
53 | * @param {ASTNode} node The Property node to check.
|
54 | * @returns {boolean} `true` if the property has been defined.
|
55 | */
|
56 | isPropertyDefined(node) {
|
57 | const entry = this.getPropertyInfo(node);
|
58 |
|
59 | return (
|
60 | (GET_KIND.test(node.kind) && entry.get) ||
|
61 | (SET_KIND.test(node.kind) && entry.set)
|
62 | );
|
63 | }
|
64 |
|
65 | /**
|
66 | * Defines the given property.
|
67 | * @param {ASTNode} node The Property node to define.
|
68 | * @returns {void}
|
69 | */
|
70 | defineProperty(node) {
|
71 | const entry = this.getPropertyInfo(node);
|
72 |
|
73 | if (GET_KIND.test(node.kind)) {
|
74 | entry.get = true;
|
75 | }
|
76 | if (SET_KIND.test(node.kind)) {
|
77 | entry.set = true;
|
78 | }
|
79 | }
|
80 | }
|
81 |
|
82 | //------------------------------------------------------------------------------
|
83 | // Rule Definition
|
84 | //------------------------------------------------------------------------------
|
85 |
|
86 | module.exports = {
|
87 | meta: {
|
88 | type: "problem",
|
89 |
|
90 | docs: {
|
91 | description: "disallow duplicate keys in object literals",
|
92 | category: "Possible Errors",
|
93 | recommended: true,
|
94 | url: "https://eslint.org/docs/rules/no-dupe-keys"
|
95 | },
|
96 |
|
97 | schema: [],
|
98 |
|
99 | messages: {
|
100 | unexpected: "Duplicate key '{{name}}'."
|
101 | }
|
102 | },
|
103 |
|
104 | create(context) {
|
105 | let info = null;
|
106 |
|
107 | return {
|
108 | ObjectExpression(node) {
|
109 | info = new ObjectInfo(info, node);
|
110 | },
|
111 | "ObjectExpression:exit"() {
|
112 | info = info.upper;
|
113 | },
|
114 |
|
115 | Property(node) {
|
116 | const name = astUtils.getStaticPropertyName(node);
|
117 |
|
118 | // Skip destructuring.
|
119 | if (node.parent.type !== "ObjectExpression") {
|
120 | return;
|
121 | }
|
122 |
|
123 | // Skip if the name is not static.
|
124 | if (name === null) {
|
125 | return;
|
126 | }
|
127 |
|
128 | // Reports if the name is defined already.
|
129 | if (info.isPropertyDefined(node)) {
|
130 | context.report({
|
131 | node: info.node,
|
132 | loc: node.key.loc,
|
133 | messageId: "unexpected",
|
134 | data: { name }
|
135 | });
|
136 | }
|
137 |
|
138 | // Update info.
|
139 | info.defineProperty(node);
|
140 | }
|
141 | };
|
142 | }
|
143 | };
|