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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// Requirements
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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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// Rule Definition
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//------------------------------------------------------------------------------
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const validIdentifier = /^[a-zA-Z_$][a-zA-Z0-9_$]*$/u;
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// `null` literal must be handled separately.
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const literalTypesToCheck = new Set(["string", "boolean"]);
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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: "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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        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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        fixable: "code",
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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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    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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        let allowPattern;
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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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         * 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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                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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                        // 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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                        // 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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                        // 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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        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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                            // 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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                            // 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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                            // 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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