%PDF-
%PDF-
Mini Shell
Mini Shell
/**
* @fileoverview Rule to disallow negating the left operand of relational operators
* @author Toru Nagashima
*/
"use strict";
//------------------------------------------------------------------------------
// Requirements
//------------------------------------------------------------------------------
const astUtils = require("./utils/ast-utils");
//------------------------------------------------------------------------------
// Helpers
//------------------------------------------------------------------------------
/**
* Checks whether the given operator is `in` or `instanceof`
* @param {string} op The operator type to check.
* @returns {boolean} `true` if the operator is `in` or `instanceof`
*/
function isInOrInstanceOfOperator(op) {
return op === "in" || op === "instanceof";
}
/**
* Checks whether the given operator is an ordering relational operator or not.
* @param {string} op The operator type to check.
* @returns {boolean} `true` if the operator is an ordering relational operator.
*/
function isOrderingRelationalOperator(op) {
return op === "<" || op === ">" || op === ">=" || op === "<=";
}
/**
* Checks whether the given node is a logical negation expression or not.
* @param {ASTNode} node The node to check.
* @returns {boolean} `true` if the node is a logical negation expression.
*/
function isNegation(node) {
return node.type === "UnaryExpression" && node.operator === "!";
}
//------------------------------------------------------------------------------
// Rule Definition
//------------------------------------------------------------------------------
/** @type {import('../shared/types').Rule} */
module.exports = {
meta: {
type: "problem",
docs: {
description: "disallow negating the left operand of relational operators",
recommended: true,
url: "https://eslint.org/docs/rules/no-unsafe-negation"
},
hasSuggestions: true,
schema: [
{
type: "object",
properties: {
enforceForOrderingRelations: {
type: "boolean",
default: false
}
},
additionalProperties: false
}
],
fixable: null,
messages: {
unexpected: "Unexpected negating the left operand of '{{operator}}' operator.",
suggestNegatedExpression: "Negate '{{operator}}' expression instead of its left operand. This changes the current behavior.",
suggestParenthesisedNegation: "Wrap negation in '()' to make the intention explicit. This preserves the current behavior."
}
},
create(context) {
const sourceCode = context.getSourceCode();
const options = context.options[0] || {};
const enforceForOrderingRelations = options.enforceForOrderingRelations === true;
return {
BinaryExpression(node) {
const operator = node.operator;
const orderingRelationRuleApplies = enforceForOrderingRelations && isOrderingRelationalOperator(operator);
if (
(isInOrInstanceOfOperator(operator) || orderingRelationRuleApplies) &&
isNegation(node.left) &&
!astUtils.isParenthesised(sourceCode, node.left)
) {
context.report({
node,
loc: node.left.loc,
messageId: "unexpected",
data: { operator },
suggest: [
{
messageId: "suggestNegatedExpression",
data: { operator },
fix(fixer) {
const negationToken = sourceCode.getFirstToken(node.left);
const fixRange = [negationToken.range[1], node.range[1]];
const text = sourceCode.text.slice(fixRange[0], fixRange[1]);
return fixer.replaceTextRange(fixRange, `(${text})`);
}
},
{
messageId: "suggestParenthesisedNegation",
fix(fixer) {
return fixer.replaceText(node.left, `(${sourceCode.getText(node.left)})`);
}
}
]
});
}
}
};
}
};
Zerion Mini Shell 1.0