/**
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* @fileoverview Rule to flag use of an lexical declarations inside a case clause
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* @author Erik Arvidsson
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*/
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"use strict";
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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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type: "suggestion",
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docs: {
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description: "disallow lexical declarations in case clauses",
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category: "Best Practices",
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recommended: true,
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url: "https://eslint.org/docs/rules/no-case-declarations"
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},
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schema: [],
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messages: {
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unexpected: "Unexpected lexical declaration in case block."
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}
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},
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create(context) {
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/**
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* Checks whether or not a node is a lexical declaration.
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* @param {ASTNode} node A direct child statement of a switch case.
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* @returns {boolean} Whether or not the node is a lexical declaration.
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*/
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function isLexicalDeclaration(node) {
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switch (node.type) {
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case "FunctionDeclaration":
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case "ClassDeclaration":
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return true;
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case "VariableDeclaration":
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return node.kind !== "var";
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default:
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return false;
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}
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}
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return {
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SwitchCase(node) {
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for (let i = 0; i < node.consequent.length; i++) {
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const statement = node.consequent[i];
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if (isLexicalDeclaration(statement)) {
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context.report({
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node: statement,
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messageId: "unexpected"
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});
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}
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}
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}
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};
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}
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};
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