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