| /** |
| * @fileoverview Rule to disallow empty functions. |
| * @author Toru Nagashima |
| */ |
| |
| "use strict"; |
| |
| //------------------------------------------------------------------------------ |
| // Requirements |
| //------------------------------------------------------------------------------ |
| |
| const astUtils = require("./utils/ast-utils"); |
| |
| //------------------------------------------------------------------------------ |
| // Helpers |
| //------------------------------------------------------------------------------ |
| |
| const ALLOW_OPTIONS = Object.freeze([ |
| "functions", |
| "arrowFunctions", |
| "generatorFunctions", |
| "methods", |
| "generatorMethods", |
| "getters", |
| "setters", |
| "constructors" |
| ]); |
| |
| /** |
| * Gets the kind of a given function node. |
| * |
| * @param {ASTNode} node - A function node to get. This is one of |
| * an ArrowFunctionExpression, a FunctionDeclaration, or a |
| * FunctionExpression. |
| * @returns {string} The kind of the function. This is one of "functions", |
| * "arrowFunctions", "generatorFunctions", "asyncFunctions", "methods", |
| * "generatorMethods", "asyncMethods", "getters", "setters", and |
| * "constructors". |
| */ |
| function getKind(node) { |
| const parent = node.parent; |
| let kind = ""; |
| |
| if (node.type === "ArrowFunctionExpression") { |
| return "arrowFunctions"; |
| } |
| |
| // Detects main kind. |
| if (parent.type === "Property") { |
| if (parent.kind === "get") { |
| return "getters"; |
| } |
| if (parent.kind === "set") { |
| return "setters"; |
| } |
| kind = parent.method ? "methods" : "functions"; |
| |
| } else if (parent.type === "MethodDefinition") { |
| if (parent.kind === "get") { |
| return "getters"; |
| } |
| if (parent.kind === "set") { |
| return "setters"; |
| } |
| if (parent.kind === "constructor") { |
| return "constructors"; |
| } |
| kind = "methods"; |
| |
| } else { |
| kind = "functions"; |
| } |
| |
| // Detects prefix. |
| let prefix = ""; |
| |
| if (node.generator) { |
| prefix = "generator"; |
| } else if (node.async) { |
| prefix = "async"; |
| } else { |
| return kind; |
| } |
| return prefix + kind[0].toUpperCase() + kind.slice(1); |
| } |
| |
| //------------------------------------------------------------------------------ |
| // Rule Definition |
| //------------------------------------------------------------------------------ |
| |
| module.exports = { |
| meta: { |
| type: "suggestion", |
| |
| docs: { |
| description: "disallow empty functions", |
| category: "Best Practices", |
| recommended: false, |
| url: "https://eslint.org/docs/rules/no-empty-function" |
| }, |
| |
| schema: [ |
| { |
| type: "object", |
| properties: { |
| allow: { |
| type: "array", |
| items: { enum: ALLOW_OPTIONS }, |
| uniqueItems: true |
| } |
| }, |
| additionalProperties: false |
| } |
| ], |
| |
| messages: { |
| unexpected: "Unexpected empty {{name}}." |
| } |
| }, |
| |
| create(context) { |
| const options = context.options[0] || {}; |
| const allowed = options.allow || []; |
| |
| const sourceCode = context.getSourceCode(); |
| |
| /** |
| * Reports a given function node if the node matches the following patterns. |
| * |
| * - Not allowed by options. |
| * - The body is empty. |
| * - The body doesn't have any comments. |
| * |
| * @param {ASTNode} node - A function node to report. This is one of |
| * an ArrowFunctionExpression, a FunctionDeclaration, or a |
| * FunctionExpression. |
| * @returns {void} |
| */ |
| function reportIfEmpty(node) { |
| const kind = getKind(node); |
| const name = astUtils.getFunctionNameWithKind(node); |
| const innerComments = sourceCode.getTokens(node.body, { |
| includeComments: true, |
| filter: astUtils.isCommentToken |
| }); |
| |
| if (allowed.indexOf(kind) === -1 && |
| node.body.type === "BlockStatement" && |
| node.body.body.length === 0 && |
| innerComments.length === 0 |
| ) { |
| context.report({ |
| node, |
| loc: node.body.loc.start, |
| messageId: "unexpected", |
| data: { name } |
| }); |
| } |
| } |
| |
| return { |
| ArrowFunctionExpression: reportIfEmpty, |
| FunctionDeclaration: reportIfEmpty, |
| FunctionExpression: reportIfEmpty |
| }; |
| } |
| }; |