177 lines
		
	
	
		
			6.6 KiB
		
	
	
	
		
			JavaScript
		
	
	
	
	
	
			
		
		
	
	
			177 lines
		
	
	
		
			6.6 KiB
		
	
	
	
		
			JavaScript
		
	
	
	
	
	
| /**
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|  * @fileoverview Rule to warn about using dot notation instead of square bracket notation when possible.
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|  * @author Josh Perez
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|  */
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| "use strict";
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| 
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| //------------------------------------------------------------------------------
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| // Requirements
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| //------------------------------------------------------------------------------
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| 
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| const astUtils = require("./utils/ast-utils");
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| const keywords = require("./utils/keywords");
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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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| const validIdentifier = /^[a-zA-Z_$][a-zA-Z0-9_$]*$/u;
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| 
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| // `null` literal must be handled separately.
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| const literalTypesToCheck = new Set(["string", "boolean"]);
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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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| 
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|         docs: {
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|             description: "Enforce dot notation whenever possible",
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|             recommended: false,
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|             url: "https://eslint.org/docs/latest/rules/dot-notation"
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|         },
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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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|                     allowKeywords: {
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|                         type: "boolean",
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|                         default: true
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|                     },
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|                     allowPattern: {
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|                         type: "string",
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|                         default: ""
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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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| 
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|         fixable: "code",
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| 
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|         messages: {
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|             useDot: "[{{key}}] is better written in dot notation.",
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|             useBrackets: ".{{key}} is a syntax error."
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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 allowKeywords = options.allowKeywords === void 0 || options.allowKeywords;
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|         const sourceCode = context.sourceCode;
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| 
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|         let allowPattern;
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| 
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|         if (options.allowPattern) {
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|             allowPattern = new RegExp(options.allowPattern, "u");
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|         }
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| 
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|         /**
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|          * Check if the property is valid dot notation
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|          * @param {ASTNode} node The dot notation node
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|          * @param {string} value Value which is to be checked
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|          * @returns {void}
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|          */
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|         function checkComputedProperty(node, value) {
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|             if (
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|                 validIdentifier.test(value) &&
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|                 (allowKeywords || !keywords.includes(String(value))) &&
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|                 !(allowPattern && allowPattern.test(value))
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|             ) {
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|                 const formattedValue = node.property.type === "Literal" ? JSON.stringify(value) : `\`${value}\``;
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| 
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|                 context.report({
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|                     node: node.property,
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|                     messageId: "useDot",
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|                     data: {
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|                         key: formattedValue
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|                     },
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|                     *fix(fixer) {
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|                         const leftBracket = sourceCode.getTokenAfter(node.object, astUtils.isOpeningBracketToken);
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|                         const rightBracket = sourceCode.getLastToken(node);
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|                         const nextToken = sourceCode.getTokenAfter(node);
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| 
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|                         // Don't perform any fixes if there are comments inside the brackets.
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|                         if (sourceCode.commentsExistBetween(leftBracket, rightBracket)) {
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|                             return;
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|                         }
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| 
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|                         // Replace the brackets by an identifier.
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|                         if (!node.optional) {
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|                             yield fixer.insertTextBefore(
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|                                 leftBracket,
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|                                 astUtils.isDecimalInteger(node.object) ? " ." : "."
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|                             );
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|                         }
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|                         yield fixer.replaceTextRange(
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|                             [leftBracket.range[0], rightBracket.range[1]],
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|                             value
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|                         );
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| 
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|                         // Insert a space after the property if it will be connected to the next token.
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|                         if (
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|                             nextToken &&
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|                             rightBracket.range[1] === nextToken.range[0] &&
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|                             !astUtils.canTokensBeAdjacent(String(value), nextToken)
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|                         ) {
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|                             yield fixer.insertTextAfter(node, " ");
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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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|             MemberExpression(node) {
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|                 if (
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|                     node.computed &&
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|                     node.property.type === "Literal" &&
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|                     (literalTypesToCheck.has(typeof node.property.value) || astUtils.isNullLiteral(node.property))
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|                 ) {
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|                     checkComputedProperty(node, node.property.value);
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|                 }
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|                 if (
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|                     node.computed &&
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|                     astUtils.isStaticTemplateLiteral(node.property)
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|                 ) {
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|                     checkComputedProperty(node, node.property.quasis[0].value.cooked);
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|                 }
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|                 if (
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|                     !allowKeywords &&
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|                     !node.computed &&
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|                     node.property.type === "Identifier" &&
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|                     keywords.includes(String(node.property.name))
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|                 ) {
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|                     context.report({
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|                         node: node.property,
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|                         messageId: "useBrackets",
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|                         data: {
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|                             key: node.property.name
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|                         },
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|                         *fix(fixer) {
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|                             const dotToken = sourceCode.getTokenBefore(node.property);
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| 
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|                             // A statement that starts with `let[` is parsed as a destructuring variable declaration, not a MemberExpression.
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|                             if (node.object.type === "Identifier" && node.object.name === "let" && !node.optional) {
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|                                 return;
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|                             }
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| 
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|                             // Don't perform any fixes if there are comments between the dot and the property name.
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|                             if (sourceCode.commentsExistBetween(dotToken, node.property)) {
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|                                 return;
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|                             }
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| 
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|                             // Replace the identifier to brackets.
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|                             if (!node.optional) {
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|                                 yield fixer.remove(dotToken);
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|                             }
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|                             yield fixer.replaceText(node.property, `["${node.property.name}"]`);
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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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