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							56 lines
						
					
					
						
							1.7 KiB
						
					
					
				
			
		
		
	
	
							56 lines
						
					
					
						
							1.7 KiB
						
					
					
				/** | 
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 * @fileoverview Rule to flag comparison where left part is the same as the right | 
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 * part. | 
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 * @author Ilya Volodin | 
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 */ | 
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 | 
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"use strict"; | 
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 | 
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//------------------------------------------------------------------------------ | 
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// Rule Definition | 
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//------------------------------------------------------------------------------ | 
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 | 
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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 comparisons where both sides are exactly the same", | 
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            category: "Best Practices", | 
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            recommended: false, | 
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            url: "https://eslint.org/docs/rules/no-self-compare" | 
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        }, | 
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 | 
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        schema: [] | 
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    }, | 
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 | 
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    create(context) { | 
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        const sourceCode = context.getSourceCode(); | 
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 | 
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        /** | 
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         * Determines whether two nodes are composed of the same tokens. | 
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         * @param {ASTNode} nodeA The first node | 
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         * @param {ASTNode} nodeB The second node | 
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         * @returns {boolean} true if the nodes have identical token representations | 
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         */ | 
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        function hasSameTokens(nodeA, nodeB) { | 
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            const tokensA = sourceCode.getTokens(nodeA); | 
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            const tokensB = sourceCode.getTokens(nodeB); | 
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 | 
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            return tokensA.length === tokensB.length && | 
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                tokensA.every((token, index) => token.type === tokensB[index].type && token.value === tokensB[index].value); | 
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        } | 
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 | 
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        return { | 
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 | 
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            BinaryExpression(node) { | 
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                const operators = new Set(["===", "==", "!==", "!=", ">", "<", ">=", "<="]); | 
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 | 
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                if (operators.has(node.operator) && hasSameTokens(node.left, node.right)) { | 
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                    context.report({ node, message: "Comparing to itself is potentially pointless." }); | 
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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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 |