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Mini Shell
Mini Shell
/**
* @fileoverview Rule to disallow a duplicate case label.
* @author Dieter Oberkofler
* @author Burak Yigit Kaya
*/
"use strict";
//------------------------------------------------------------------------------
// Requirements
//------------------------------------------------------------------------------
const astUtils = require("./utils/ast-utils");
//------------------------------------------------------------------------------
// Rule Definition
//------------------------------------------------------------------------------
/** @type {import('../types').Rule.RuleModule} */
module.exports = {
meta: {
type: "problem",
docs: {
description: "Disallow duplicate case labels",
recommended: true,
url: "https://eslint.org/docs/latest/rules/no-duplicate-case",
},
schema: [],
messages: {
unexpected: "Duplicate case label.",
},
},
create(context) {
const sourceCode = context.sourceCode;
/**
* Determines whether the two given nodes are considered to be equal.
* @param {ASTNode} a First node.
* @param {ASTNode} b Second node.
* @returns {boolean} `true` if the nodes are considered to be equal.
*/
function equal(a, b) {
if (a.type !== b.type) {
return false;
}
return astUtils.equalTokens(a, b, sourceCode);
}
return {
SwitchStatement(node) {
const previousTests = [];
for (const switchCase of node.cases) {
if (switchCase.test) {
const test = switchCase.test;
if (
previousTests.some(previousTest =>
equal(previousTest, test),
)
) {
context.report({
node: switchCase,
messageId: "unexpected",
});
} else {
previousTests.push(test);
}
}
}
},
};
},
};
Zerion Mini Shell 1.0