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/**
* @fileoverview A rule to warn against using arrow functions when they could be
* confused with comparisons
* @author Jxck <https://github.com/Jxck>
*/
"use strict";
const astUtils = require("./utils/ast-utils.js");
//------------------------------------------------------------------------------
// Helpers
//------------------------------------------------------------------------------
/**
* Checks whether or not a node is a conditional expression.
* @param {ASTNode} node node to test
* @returns {boolean} `true` if the node is a conditional expression.
*/
function isConditional(node) {
return node && node.type === "ConditionalExpression";
}
//------------------------------------------------------------------------------
// Rule Definition
//------------------------------------------------------------------------------
/** @type {import('../shared/types').Rule} */
module.exports = {
meta: {
type: "suggestion",
docs: {
description: "Disallow arrow functions where they could be confused with comparisons",
recommended: false,
url: "https://eslint.org/docs/latest/rules/no-confusing-arrow"
},
fixable: "code",
schema: [{
type: "object",
properties: {
allowParens: { type: "boolean", default: true },
onlyOneSimpleParam: { type: "boolean", default: false }
},
additionalProperties: false
}],
messages: {
confusing: "Arrow function used ambiguously with a conditional expression."
}
},
create(context) {
const config = context.options[0] || {};
const allowParens = config.allowParens || (config.allowParens === void 0);
const onlyOneSimpleParam = config.onlyOneSimpleParam;
const sourceCode = context.sourceCode;
/**
* Reports if an arrow function contains an ambiguous conditional.
* @param {ASTNode} node A node to check and report.
* @returns {void}
*/
function checkArrowFunc(node) {
const body = node.body;
if (isConditional(body) &&
!(allowParens && astUtils.isParenthesised(sourceCode, body)) &&
!(onlyOneSimpleParam && !(node.params.length === 1 && node.params[0].type === "Identifier"))) {
context.report({
node,
messageId: "confusing",
fix(fixer) {
// if `allowParens` is not set to true don't bother wrapping in parens
return allowParens && fixer.replaceText(node.body, `(${sourceCode.getText(node.body)})`);
}
});
}
}
return {
ArrowFunctionExpression: checkArrowFunc
};
}
};