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eb39fafa DC |
1 | /** |
2 | * @fileoverview Rule to define spacing before/after arrow function's arrow. | |
3 | * @author Jxck | |
4 | */ | |
5 | "use strict"; | |
6 | ||
7 | //------------------------------------------------------------------------------ | |
8 | // Requirements | |
9 | //------------------------------------------------------------------------------ | |
10 | ||
11 | const astUtils = require("./utils/ast-utils"); | |
12 | ||
13 | //------------------------------------------------------------------------------ | |
14 | // Rule Definition | |
15 | //------------------------------------------------------------------------------ | |
16 | ||
34eeec05 | 17 | /** @type {import('../shared/types').Rule} */ |
eb39fafa DC |
18 | module.exports = { |
19 | meta: { | |
20 | type: "layout", | |
21 | ||
22 | docs: { | |
8f9d1d4d | 23 | description: "Enforce consistent spacing before and after the arrow in arrow functions", |
eb39fafa | 24 | recommended: false, |
f2a92ac6 | 25 | url: "https://eslint.org/docs/latest/rules/arrow-spacing" |
eb39fafa DC |
26 | }, |
27 | ||
28 | fixable: "whitespace", | |
29 | ||
30 | schema: [ | |
31 | { | |
32 | type: "object", | |
33 | properties: { | |
34 | before: { | |
35 | type: "boolean", | |
36 | default: true | |
37 | }, | |
38 | after: { | |
39 | type: "boolean", | |
40 | default: true | |
41 | } | |
42 | }, | |
43 | additionalProperties: false | |
44 | } | |
45 | ], | |
46 | ||
47 | messages: { | |
48 | expectedBefore: "Missing space before =>.", | |
49 | unexpectedBefore: "Unexpected space before =>.", | |
50 | ||
51 | expectedAfter: "Missing space after =>.", | |
52 | unexpectedAfter: "Unexpected space after =>." | |
53 | } | |
54 | }, | |
55 | ||
56 | create(context) { | |
57 | ||
58 | // merge rules with default | |
59 | const rule = Object.assign({}, context.options[0]); | |
60 | ||
61 | rule.before = rule.before !== false; | |
62 | rule.after = rule.after !== false; | |
63 | ||
f2a92ac6 | 64 | const sourceCode = context.sourceCode; |
eb39fafa DC |
65 | |
66 | /** | |
67 | * Get tokens of arrow(`=>`) and before/after arrow. | |
68 | * @param {ASTNode} node The arrow function node. | |
69 | * @returns {Object} Tokens of arrow and before/after arrow. | |
70 | */ | |
71 | function getTokens(node) { | |
72 | const arrow = sourceCode.getTokenBefore(node.body, astUtils.isArrowToken); | |
73 | ||
74 | return { | |
75 | before: sourceCode.getTokenBefore(arrow), | |
76 | arrow, | |
77 | after: sourceCode.getTokenAfter(arrow) | |
78 | }; | |
79 | } | |
80 | ||
81 | /** | |
82 | * Count spaces before/after arrow(`=>`) token. | |
83 | * @param {Object} tokens Tokens before/after arrow. | |
84 | * @returns {Object} count of space before/after arrow. | |
85 | */ | |
86 | function countSpaces(tokens) { | |
87 | const before = tokens.arrow.range[0] - tokens.before.range[1]; | |
88 | const after = tokens.after.range[0] - tokens.arrow.range[1]; | |
89 | ||
90 | return { before, after }; | |
91 | } | |
92 | ||
93 | /** | |
94 | * Determines whether space(s) before after arrow(`=>`) is satisfy rule. | |
95 | * if before/after value is `true`, there should be space(s). | |
96 | * if before/after value is `false`, there should be no space. | |
97 | * @param {ASTNode} node The arrow function node. | |
98 | * @returns {void} | |
99 | */ | |
100 | function spaces(node) { | |
101 | const tokens = getTokens(node); | |
102 | const countSpace = countSpaces(tokens); | |
103 | ||
104 | if (rule.before) { | |
105 | ||
106 | // should be space(s) before arrow | |
107 | if (countSpace.before === 0) { | |
108 | context.report({ | |
109 | node: tokens.before, | |
110 | messageId: "expectedBefore", | |
111 | fix(fixer) { | |
112 | return fixer.insertTextBefore(tokens.arrow, " "); | |
113 | } | |
114 | }); | |
115 | } | |
116 | } else { | |
117 | ||
118 | // should be no space before arrow | |
119 | if (countSpace.before > 0) { | |
120 | context.report({ | |
121 | node: tokens.before, | |
122 | messageId: "unexpectedBefore", | |
123 | fix(fixer) { | |
124 | return fixer.removeRange([tokens.before.range[1], tokens.arrow.range[0]]); | |
125 | } | |
126 | }); | |
127 | } | |
128 | } | |
129 | ||
130 | if (rule.after) { | |
131 | ||
132 | // should be space(s) after arrow | |
133 | if (countSpace.after === 0) { | |
134 | context.report({ | |
135 | node: tokens.after, | |
136 | messageId: "expectedAfter", | |
137 | fix(fixer) { | |
138 | return fixer.insertTextAfter(tokens.arrow, " "); | |
139 | } | |
140 | }); | |
141 | } | |
142 | } else { | |
143 | ||
144 | // should be no space after arrow | |
145 | if (countSpace.after > 0) { | |
146 | context.report({ | |
147 | node: tokens.after, | |
148 | messageId: "unexpectedAfter", | |
149 | fix(fixer) { | |
150 | return fixer.removeRange([tokens.arrow.range[1], tokens.after.range[0]]); | |
151 | } | |
152 | }); | |
153 | } | |
154 | } | |
155 | } | |
156 | ||
157 | return { | |
158 | ArrowFunctionExpression: spaces | |
159 | }; | |
160 | } | |
161 | }; |