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							6.1 KiB
						
					
					
				
			
		
		
	
	
							183 lines
						
					
					
						
							6.1 KiB
						
					
					
				/** | 
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 * @fileoverview Rule to warn when a function expression does not have a name. | 
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 * @author Kyle T. Nunery | 
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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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// Requirements | 
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//------------------------------------------------------------------------------ | 
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 | 
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const astUtils = require("./utils/ast-utils"); | 
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 | 
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/** | 
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 * Checks whether or not a given variable is a function name. | 
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 * @param {eslint-scope.Variable} variable A variable to check. | 
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 * @returns {boolean} `true` if the variable is a function name. | 
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 */ | 
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function isFunctionName(variable) { | 
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    return variable && variable.defs[0].type === "FunctionName"; | 
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} | 
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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: "suggestion", | 
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 | 
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        docs: { | 
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            description: "require or disallow named `function` expressions", | 
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            category: "Stylistic Issues", | 
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            recommended: false, | 
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            url: "https://eslint.org/docs/rules/func-names" | 
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        }, | 
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 | 
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        schema: { | 
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            definitions: { | 
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                value: { | 
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                    enum: [ | 
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                        "always", | 
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                        "as-needed", | 
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                        "never" | 
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                    ] | 
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                } | 
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            }, | 
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            items: [ | 
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                { | 
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                    $ref: "#/definitions/value" | 
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                }, | 
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                { | 
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                    type: "object", | 
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                    properties: { | 
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                        generators: { | 
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                            $ref: "#/definitions/value" | 
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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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 | 
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        messages: { | 
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            unnamed: "Unexpected unnamed {{name}}.", | 
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            named: "Unexpected named {{name}}." | 
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        } | 
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    }, | 
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 | 
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    create(context) { | 
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 | 
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        const sourceCode = context.getSourceCode(); | 
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 | 
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        /** | 
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         * Returns the config option for the given node. | 
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         * @param {ASTNode} node A node to get the config for. | 
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         * @returns {string} The config option. | 
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         */ | 
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        function getConfigForNode(node) { | 
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            if ( | 
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                node.generator && | 
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                context.options.length > 1 && | 
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                context.options[1].generators | 
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            ) { | 
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                return context.options[1].generators; | 
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            } | 
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 | 
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            return context.options[0] || "always"; | 
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        } | 
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 | 
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        /** | 
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         * Determines whether the current FunctionExpression node is a get, set, or | 
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         * shorthand method in an object literal or a class. | 
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         * @param {ASTNode} node A node to check. | 
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         * @returns {boolean} True if the node is a get, set, or shorthand method. | 
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         */ | 
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        function isObjectOrClassMethod(node) { | 
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            const parent = node.parent; | 
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 | 
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            return (parent.type === "MethodDefinition" || ( | 
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                parent.type === "Property" && ( | 
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                    parent.method || | 
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                    parent.kind === "get" || | 
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                    parent.kind === "set" | 
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                ) | 
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            )); | 
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        } | 
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 | 
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        /** | 
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         * Determines whether the current FunctionExpression node has a name that would be | 
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         * inferred from context in a conforming ES6 environment. | 
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         * @param {ASTNode} node A node to check. | 
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         * @returns {boolean} True if the node would have a name assigned automatically. | 
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         */ | 
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        function hasInferredName(node) { | 
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            const parent = node.parent; | 
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 | 
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            return isObjectOrClassMethod(node) || | 
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                (parent.type === "VariableDeclarator" && parent.id.type === "Identifier" && parent.init === node) || | 
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                (parent.type === "Property" && parent.value === node) || | 
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                (parent.type === "AssignmentExpression" && parent.left.type === "Identifier" && parent.right === node) || | 
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                (parent.type === "ExportDefaultDeclaration" && parent.declaration === node) || | 
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                (parent.type === "AssignmentPattern" && parent.right === node); | 
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        } | 
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 | 
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        /** | 
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         * Reports that an unnamed function should be named | 
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         * @param {ASTNode} node The node to report in the event of an error. | 
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         * @returns {void} | 
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         */ | 
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        function reportUnexpectedUnnamedFunction(node) { | 
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            context.report({ | 
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                node, | 
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                messageId: "unnamed", | 
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                loc: astUtils.getFunctionHeadLoc(node, sourceCode), | 
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                data: { name: astUtils.getFunctionNameWithKind(node) } | 
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            }); | 
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        } | 
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 | 
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        /** | 
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         * Reports that a named function should be unnamed | 
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         * @param {ASTNode} node The node to report in the event of an error. | 
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         * @returns {void} | 
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         */ | 
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        function reportUnexpectedNamedFunction(node) { | 
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            context.report({ | 
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                node, | 
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                messageId: "named", | 
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                loc: astUtils.getFunctionHeadLoc(node, sourceCode), | 
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                data: { name: astUtils.getFunctionNameWithKind(node) } | 
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            }); | 
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        } | 
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 | 
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        return { | 
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            "FunctionExpression:exit"(node) { | 
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 | 
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                // Skip recursive functions. | 
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                const nameVar = context.getDeclaredVariables(node)[0]; | 
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 | 
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                if (isFunctionName(nameVar) && nameVar.references.length > 0) { | 
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                    return; | 
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                } | 
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 | 
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                const hasName = Boolean(node.id && node.id.name); | 
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                const config = getConfigForNode(node); | 
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 | 
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                if (config === "never") { | 
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                    if (hasName) { | 
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                        reportUnexpectedNamedFunction(node); | 
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                    } | 
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                } else if (config === "as-needed") { | 
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                    if (!hasName && !hasInferredName(node)) { | 
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                        reportUnexpectedUnnamedFunction(node); | 
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                    } | 
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                } else { | 
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                    if (!hasName && !isObjectOrClassMethod(node)) { | 
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                        reportUnexpectedUnnamedFunction(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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 |