227 lines
7.5 KiB
JavaScript
227 lines
7.5 KiB
JavaScript
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/**
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* @fileoverview Rule to disallow mixed binary operators.
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* @author Toru Nagashima
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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 astUtils = require("./utils/ast-utils.js");
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//------------------------------------------------------------------------------
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// Helpers
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//------------------------------------------------------------------------------
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const ARITHMETIC_OPERATORS = ["+", "-", "*", "/", "%", "**"];
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const BITWISE_OPERATORS = ["&", "|", "^", "~", "<<", ">>", ">>>"];
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const COMPARISON_OPERATORS = ["==", "!=", "===", "!==", ">", ">=", "<", "<="];
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const LOGICAL_OPERATORS = ["&&", "||"];
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const RELATIONAL_OPERATORS = ["in", "instanceof"];
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const TERNARY_OPERATOR = ["?:"];
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const COALESCE_OPERATOR = ["??"];
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const ALL_OPERATORS = [].concat(
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ARITHMETIC_OPERATORS,
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BITWISE_OPERATORS,
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COMPARISON_OPERATORS,
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LOGICAL_OPERATORS,
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RELATIONAL_OPERATORS,
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TERNARY_OPERATOR,
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COALESCE_OPERATOR
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);
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const DEFAULT_GROUPS = [
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ARITHMETIC_OPERATORS,
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BITWISE_OPERATORS,
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COMPARISON_OPERATORS,
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LOGICAL_OPERATORS,
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RELATIONAL_OPERATORS
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];
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const TARGET_NODE_TYPE = /^(?:Binary|Logical|Conditional)Expression$/u;
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/**
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* Normalizes options.
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* @param {Object|undefined} options A options object to normalize.
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* @returns {Object} Normalized option object.
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*/
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function normalizeOptions(options = {}) {
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const hasGroups = options.groups && options.groups.length > 0;
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const groups = hasGroups ? options.groups : DEFAULT_GROUPS;
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const allowSamePrecedence = options.allowSamePrecedence !== false;
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return {
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groups,
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allowSamePrecedence
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};
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}
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/**
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* Checks whether any group which includes both given operator exists or not.
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* @param {Array<string[]>} groups A list of groups to check.
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* @param {string} left An operator.
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* @param {string} right Another operator.
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* @returns {boolean} `true` if such group existed.
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*/
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function includesBothInAGroup(groups, left, right) {
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return groups.some(group => group.includes(left) && group.includes(right));
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}
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/**
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* Checks whether the given node is a conditional expression and returns the test node else the left node.
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* @param {ASTNode} node A node which can be a BinaryExpression or a LogicalExpression node.
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* This parent node can be BinaryExpression, LogicalExpression
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* , or a ConditionalExpression node
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* @returns {ASTNode} node the appropriate node(left or test).
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*/
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function getChildNode(node) {
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return node.type === "ConditionalExpression" ? node.test : node.left;
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}
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//------------------------------------------------------------------------------
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// Rule Definition
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//------------------------------------------------------------------------------
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/** @type {import('../shared/types').Rule} */
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module.exports = {
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meta: {
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type: "suggestion",
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docs: {
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description: "Disallow mixed binary operators",
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recommended: false,
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url: "https://eslint.org/docs/latest/rules/no-mixed-operators"
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},
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schema: [
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{
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type: "object",
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properties: {
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groups: {
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type: "array",
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items: {
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type: "array",
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items: { enum: ALL_OPERATORS },
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minItems: 2,
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uniqueItems: true
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},
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uniqueItems: true
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},
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allowSamePrecedence: {
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type: "boolean",
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default: true
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}
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},
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additionalProperties: false
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}
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],
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messages: {
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unexpectedMixedOperator: "Unexpected mix of '{{leftOperator}}' and '{{rightOperator}}'. Use parentheses to clarify the intended order of operations."
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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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const options = normalizeOptions(context.options[0]);
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/**
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* Checks whether a given node should be ignored by options or not.
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* @param {ASTNode} node A node to check. This is a BinaryExpression
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* node or a LogicalExpression node. This parent node is one of
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* them, too.
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* @returns {boolean} `true` if the node should be ignored.
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*/
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function shouldIgnore(node) {
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const a = node;
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const b = node.parent;
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return (
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!includesBothInAGroup(options.groups, a.operator, b.type === "ConditionalExpression" ? "?:" : b.operator) ||
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(
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options.allowSamePrecedence &&
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astUtils.getPrecedence(a) === astUtils.getPrecedence(b)
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)
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);
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}
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/**
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* Checks whether the operator of a given node is mixed with parent
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* node's operator or not.
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* @param {ASTNode} node A node to check. This is a BinaryExpression
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* node or a LogicalExpression node. This parent node is one of
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* them, too.
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* @returns {boolean} `true` if the node was mixed.
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*/
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function isMixedWithParent(node) {
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return (
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node.operator !== node.parent.operator &&
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!astUtils.isParenthesised(sourceCode, node)
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);
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}
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/**
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* Gets the operator token of a given node.
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* @param {ASTNode} node A node to check. This is a BinaryExpression
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* node or a LogicalExpression node.
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* @returns {Token} The operator token of the node.
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*/
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function getOperatorToken(node) {
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return sourceCode.getTokenAfter(getChildNode(node), astUtils.isNotClosingParenToken);
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}
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/**
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* Reports both the operator of a given node and the operator of the
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* parent node.
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* @param {ASTNode} node A node to check. This is a BinaryExpression
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* node or a LogicalExpression node. This parent node is one of
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* them, too.
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* @returns {void}
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*/
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function reportBothOperators(node) {
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const parent = node.parent;
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const left = (getChildNode(parent) === node) ? node : parent;
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const right = (getChildNode(parent) !== node) ? node : parent;
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const data = {
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leftOperator: left.operator || "?:",
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rightOperator: right.operator || "?:"
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};
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context.report({
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node: left,
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loc: getOperatorToken(left).loc,
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messageId: "unexpectedMixedOperator",
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data
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});
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context.report({
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node: right,
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loc: getOperatorToken(right).loc,
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messageId: "unexpectedMixedOperator",
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data
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});
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}
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/**
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* Checks between the operator of this node and the operator of the
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* parent node.
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* @param {ASTNode} node A node to check.
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* @returns {void}
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*/
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function check(node) {
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if (
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TARGET_NODE_TYPE.test(node.parent.type) &&
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isMixedWithParent(node) &&
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!shouldIgnore(node)
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) {
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reportBothOperators(node);
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}
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}
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return {
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BinaryExpression: check,
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LogicalExpression: check
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};
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}
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};
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