158 lines
3.8 KiB
JavaScript
158 lines
3.8 KiB
JavaScript
/**
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* @fileoverview The rule should warn against code that tries to compare against -0.
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* @author Aladdin-ADD <hh_2013@foxmail.com>
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*/
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"use strict";
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//------------------------------------------------------------------------------
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// Requirements
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//------------------------------------------------------------------------------
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const { getVariableByName } = require("./utils/ast-utils");
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//------------------------------------------------------------------------------
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// Rule Definition
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//------------------------------------------------------------------------------
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/** @type {import('../types').Rule.RuleModule} */
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module.exports = {
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meta: {
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type: "problem",
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docs: {
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description: "Disallow comparing against `-0`",
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recommended: true,
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url: "https://eslint.org/docs/latest/rules/no-compare-neg-zero",
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},
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fixable: null,
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hasSuggestions: true,
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schema: [],
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messages: {
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unexpected:
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"Do not use the '{{operator}}' operator to compare against -0.",
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suggestRemoveMinus:
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"Replace '-0' with '0' (keeps the current comparison behavior).",
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suggestObjectIs:
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"Replace with 'Object.is()' (changes the comparison to distinguish -0 from +0).",
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suggestNotObjectIs:
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"Replace with '!Object.is()' (changes the comparison to distinguish -0 from +0).",
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},
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},
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create(context) {
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const sourceCode = context.sourceCode;
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//--------------------------------------------------------------------------
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// Helpers
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//--------------------------------------------------------------------------
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/**
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* Checks a given node is -0
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* @param {ASTNode} node A node to check.
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* @returns {boolean} `true` if the node is -0.
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*/
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function isNegZero(node) {
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return (
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node.type === "UnaryExpression" &&
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node.operator === "-" &&
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node.argument.type === "Literal" &&
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node.argument.value === 0
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);
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}
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/**
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* Gets the source text of an operand, keeping parentheses where required.
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* @param {ASTNode} operand A comparison operand node.
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* @returns {string} The source text of the operand.
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*/
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function getOperandText(operand) {
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const text = sourceCode.getText(operand);
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return operand.type === "SequenceExpression" ? `(${text})` : text;
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}
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const OPERATORS_TO_CHECK = new Set([
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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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"!==",
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]);
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return {
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BinaryExpression(node) {
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if (!OPERATORS_TO_CHECK.has(node.operator)) {
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return;
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}
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const leftIsNegZero = isNegZero(node.left);
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const rightIsNegZero = isNegZero(node.right);
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if (!leftIsNegZero && !rightIsNegZero) {
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return;
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}
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context.report({
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node,
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messageId: "unexpected",
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data: { operator: node.operator },
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suggest: [
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{
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messageId: "suggestRemoveMinus",
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*fix(fixer) {
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if (leftIsNegZero) {
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yield fixer.replaceText(node.left, "0");
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}
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if (rightIsNegZero) {
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yield fixer.replaceText(node.right, "0");
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}
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},
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},
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{
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messageId:
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node.operator === "==="
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? "suggestObjectIs"
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: "suggestNotObjectIs",
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fix(fixer) {
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if (
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(node.operator !== "===" &&
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node.operator !== "!==") ||
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sourceCode.getCommentsInside(node).length >
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0
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) {
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return null;
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}
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const objectVariable = getVariableByName(
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sourceCode.getScope(node),
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"Object",
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);
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if (
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!objectVariable ||
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objectVariable.identifiers.length > 0
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) {
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return null;
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}
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const negation =
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node.operator === "===" ? "" : "!";
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return fixer.replaceText(
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node,
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`${negation}Object.is(${getOperandText(node.left)}, ${getOperandText(node.right)})`,
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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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},
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};
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