2 * @fileoverview Rule to check the spacing around the * in generator functions.
3 * @author Jamund Ferguson
8 //------------------------------------------------------------------------------
10 //------------------------------------------------------------------------------
12 const OVERRIDE_SCHEMA = {
15 enum: ["before", "after", "both", "neither"]
20 before: { type: "boolean" },
21 after: { type: "boolean" }
23 additionalProperties: false
33 description: "enforce consistent spacing around `*` operators in generator functions",
34 category: "ECMAScript 6",
36 url: "https://eslint.org/docs/rules/generator-star-spacing"
39 fixable: "whitespace",
45 enum: ["before", "after", "both", "neither"]
50 before: { type: "boolean" },
51 after: { type: "boolean" },
52 named: OVERRIDE_SCHEMA,
53 anonymous: OVERRIDE_SCHEMA,
54 method: OVERRIDE_SCHEMA
56 additionalProperties: false
63 missingBefore: "Missing space before *.",
64 missingAfter: "Missing space after *.",
65 unexpectedBefore: "Unexpected space before *.",
66 unexpectedAfter: "Unexpected space after *."
72 const optionDefinitions = {
73 before: { before: true, after: false },
74 after: { before: false, after: true },
75 both: { before: true, after: true },
76 neither: { before: false, after: false }
80 * Returns resolved option definitions based on an option and defaults
81 * @param {any} option The option object or string value
82 * @param {Object} defaults The defaults to use if options are not present
83 * @returns {Object} the resolved object definition
85 function optionToDefinition(option, defaults) {
90 return typeof option === "string"
91 ? optionDefinitions[option]
92 : Object.assign({}, defaults, option);
95 const modes = (function(option) {
96 const defaults = optionToDefinition(option, optionDefinitions.before);
99 named: optionToDefinition(option.named, defaults),
100 anonymous: optionToDefinition(option.anonymous, defaults),
101 method: optionToDefinition(option.method, defaults)
103 }(context.options[0] || {}));
105 const sourceCode = context.getSourceCode();
108 * Checks if the given token is a star token or not.
109 * @param {Token} token The token to check.
110 * @returns {boolean} `true` if the token is a star token.
112 function isStarToken(token) {
113 return token.value === "*" && token.type === "Punctuator";
117 * Gets the generator star token of the given function node.
118 * @param {ASTNode} node The function node to get.
119 * @returns {Token} Found star token.
121 function getStarToken(node) {
122 return sourceCode.getFirstToken(
123 (node.parent.method || node.parent.type === "MethodDefinition") ? node.parent : node,
129 * capitalize a given string.
130 * @param {string} str the given string.
131 * @returns {string} the capitalized string.
133 function capitalize(str) {
134 return str[0].toUpperCase() + str.slice(1);
138 * Checks the spacing between two tokens before or after the star token.
139 * @param {string} kind Either "named", "anonymous", or "method"
140 * @param {string} side Either "before" or "after".
141 * @param {Token} leftToken `function` keyword token if side is "before", or
142 * star token if side is "after".
143 * @param {Token} rightToken Star token if side is "before", or identifier
144 * token if side is "after".
147 function checkSpacing(kind, side, leftToken, rightToken) {
148 if (!!(rightToken.range[0] - leftToken.range[1]) !== modes[kind][side]) {
149 const after = leftToken.value === "*";
150 const spaceRequired = modes[kind][side];
151 const node = after ? leftToken : rightToken;
152 const messageId = `${spaceRequired ? "missing" : "unexpected"}${capitalize(side)}`;
160 return fixer.insertTextAfter(node, " ");
162 return fixer.insertTextBefore(node, " ");
164 return fixer.removeRange([leftToken.range[1], rightToken.range[0]]);
171 * Enforces the spacing around the star if node is a generator function.
172 * @param {ASTNode} node A function expression or declaration node.
175 function checkFunction(node) {
176 if (!node.generator) {
180 const starToken = getStarToken(node);
181 const prevToken = sourceCode.getTokenBefore(starToken);
182 const nextToken = sourceCode.getTokenAfter(starToken);
186 if (node.parent.type === "MethodDefinition" || (node.parent.type === "Property" && node.parent.method)) {
188 } else if (!node.id) {
192 // Only check before when preceded by `function`|`static` keyword
193 if (!(kind === "method" && starToken === sourceCode.getFirstToken(node.parent))) {
194 checkSpacing(kind, "before", prevToken, starToken);
197 checkSpacing(kind, "after", starToken, nextToken);
201 FunctionDeclaration: checkFunction,
202 FunctionExpression: checkFunction