206 lines
		
	
	
		
			7.0 KiB
		
	
	
	
		
			JavaScript
		
	
	
	
	
	
			
		
		
	
	
			206 lines
		
	
	
		
			7.0 KiB
		
	
	
	
		
			JavaScript
		
	
	
	
	
	
| /**
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|  * @fileoverview Rule to disallow unsafe optional chaining
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|  * @author Yeon JuAn
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|  */
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| 
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| "use strict";
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| 
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| const UNSAFE_ARITHMETIC_OPERATORS = new Set(["+", "-", "/", "*", "%", "**"]);
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| const UNSAFE_ASSIGNMENT_OPERATORS = new Set(["+=", "-=", "/=", "*=", "%=", "**="]);
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| const UNSAFE_RELATIONAL_OPERATORS = new Set(["in", "instanceof"]);
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| 
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| /**
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|  * Checks whether a node is a destructuring pattern or not
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|  * @param {ASTNode} node node to check
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|  * @returns {boolean} `true` if a node is a destructuring pattern, otherwise `false`
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|  */
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| function isDestructuringPattern(node) {
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|     return node.type === "ObjectPattern" || node.type === "ArrayPattern";
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| }
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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: "problem",
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| 
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|         docs: {
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|             description: "Disallow use of optional chaining in contexts where the `undefined` value is not allowed",
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|             recommended: true,
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|             url: "https://eslint.org/docs/latest/rules/no-unsafe-optional-chaining"
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|         },
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|         schema: [{
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|             type: "object",
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|             properties: {
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|                 disallowArithmeticOperators: {
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|                     type: "boolean",
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|                     default: false
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|                 }
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|             },
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|             additionalProperties: false
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|         }],
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|         fixable: null,
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|         messages: {
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|             unsafeOptionalChain: "Unsafe usage of optional chaining. If it short-circuits with 'undefined' the evaluation will throw TypeError.",
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|             unsafeArithmetic: "Unsafe arithmetic operation on optional chaining. It can result in NaN."
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|         }
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|     },
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| 
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|     create(context) {
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|         const options = context.options[0] || {};
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|         const disallowArithmeticOperators = (options.disallowArithmeticOperators) || false;
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| 
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|         /**
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|          * Reports unsafe usage of optional chaining
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|          * @param {ASTNode} node node to report
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|          * @returns {void}
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|          */
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|         function reportUnsafeUsage(node) {
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|             context.report({
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|                 messageId: "unsafeOptionalChain",
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|                 node
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|             });
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|         }
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| 
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|         /**
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|          * Reports unsafe arithmetic operation on optional chaining
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|          * @param {ASTNode} node node to report
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|          * @returns {void}
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|          */
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|         function reportUnsafeArithmetic(node) {
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|             context.report({
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|                 messageId: "unsafeArithmetic",
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|                 node
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|             });
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|         }
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| 
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|         /**
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|          * Checks and reports if a node can short-circuit with `undefined` by optional chaining.
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|          * @param {ASTNode} [node] node to check
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|          * @param {Function} reportFunc report function
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|          * @returns {void}
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|          */
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|         function checkUndefinedShortCircuit(node, reportFunc) {
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|             if (!node) {
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|                 return;
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|             }
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|             switch (node.type) {
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|                 case "LogicalExpression":
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|                     if (node.operator === "||" || node.operator === "??") {
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|                         checkUndefinedShortCircuit(node.right, reportFunc);
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|                     } else if (node.operator === "&&") {
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|                         checkUndefinedShortCircuit(node.left, reportFunc);
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|                         checkUndefinedShortCircuit(node.right, reportFunc);
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|                     }
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|                     break;
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|                 case "SequenceExpression":
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|                     checkUndefinedShortCircuit(
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|                         node.expressions[node.expressions.length - 1],
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|                         reportFunc
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|                     );
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|                     break;
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|                 case "ConditionalExpression":
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|                     checkUndefinedShortCircuit(node.consequent, reportFunc);
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|                     checkUndefinedShortCircuit(node.alternate, reportFunc);
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|                     break;
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|                 case "AwaitExpression":
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|                     checkUndefinedShortCircuit(node.argument, reportFunc);
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|                     break;
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|                 case "ChainExpression":
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|                     reportFunc(node);
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|                     break;
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|                 default:
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|                     break;
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|             }
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|         }
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| 
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|         /**
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|          * Checks unsafe usage of optional chaining
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|          * @param {ASTNode} node node to check
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|          * @returns {void}
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|          */
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|         function checkUnsafeUsage(node) {
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|             checkUndefinedShortCircuit(node, reportUnsafeUsage);
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|         }
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| 
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|         /**
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|          * Checks unsafe arithmetic operations on optional chaining
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|          * @param {ASTNode} node node to check
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|          * @returns {void}
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|          */
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|         function checkUnsafeArithmetic(node) {
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|             checkUndefinedShortCircuit(node, reportUnsafeArithmetic);
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|         }
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| 
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|         return {
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|             "AssignmentExpression, AssignmentPattern"(node) {
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|                 if (isDestructuringPattern(node.left)) {
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|                     checkUnsafeUsage(node.right);
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|                 }
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|             },
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|             "ClassDeclaration, ClassExpression"(node) {
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|                 checkUnsafeUsage(node.superClass);
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|             },
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|             CallExpression(node) {
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|                 if (!node.optional) {
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|                     checkUnsafeUsage(node.callee);
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|                 }
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|             },
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|             NewExpression(node) {
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|                 checkUnsafeUsage(node.callee);
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|             },
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|             VariableDeclarator(node) {
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|                 if (isDestructuringPattern(node.id)) {
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|                     checkUnsafeUsage(node.init);
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|                 }
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|             },
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|             MemberExpression(node) {
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|                 if (!node.optional) {
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|                     checkUnsafeUsage(node.object);
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|                 }
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|             },
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|             TaggedTemplateExpression(node) {
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|                 checkUnsafeUsage(node.tag);
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|             },
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|             ForOfStatement(node) {
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|                 checkUnsafeUsage(node.right);
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|             },
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|             SpreadElement(node) {
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|                 if (node.parent && node.parent.type !== "ObjectExpression") {
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|                     checkUnsafeUsage(node.argument);
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|                 }
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|             },
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|             BinaryExpression(node) {
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|                 if (UNSAFE_RELATIONAL_OPERATORS.has(node.operator)) {
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|                     checkUnsafeUsage(node.right);
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|                 }
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|                 if (
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|                     disallowArithmeticOperators &&
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|                     UNSAFE_ARITHMETIC_OPERATORS.has(node.operator)
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|                 ) {
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|                     checkUnsafeArithmetic(node.right);
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|                     checkUnsafeArithmetic(node.left);
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|                 }
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|             },
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|             WithStatement(node) {
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|                 checkUnsafeUsage(node.object);
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|             },
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|             UnaryExpression(node) {
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|                 if (
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|                     disallowArithmeticOperators &&
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|                     UNSAFE_ARITHMETIC_OPERATORS.has(node.operator)
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|                 ) {
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|                     checkUnsafeArithmetic(node.argument);
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|                 }
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|             },
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|             AssignmentExpression(node) {
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|                 if (
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|                     disallowArithmeticOperators &&
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|                     UNSAFE_ASSIGNMENT_OPERATORS.has(node.operator)
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|                 ) {
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|                     checkUnsafeArithmetic(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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