+++ /dev/null
-/**
- * @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
-//------------------------------------------------------------------------------
-
-module.exports = {
- meta: {
- type: "problem",
-
- docs: {
- description: "disallow negating the left operand of relational operators",
- category: "Possible Errors",
- recommended: true,
- url: "https://eslint.org/docs/rules/no-unsafe-negation",
- suggestion: 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)})`);
- }
- }
- ]
- });
- }
- }
- };
- }
-};