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Diffstat (limited to 'tools/node_modules/eslint/lib/rules/no-setter-return.js')
-rw-r--r-- | tools/node_modules/eslint/lib/rules/no-setter-return.js | 227 |
1 files changed, 227 insertions, 0 deletions
diff --git a/tools/node_modules/eslint/lib/rules/no-setter-return.js b/tools/node_modules/eslint/lib/rules/no-setter-return.js new file mode 100644 index 0000000000..e0948696c3 --- /dev/null +++ b/tools/node_modules/eslint/lib/rules/no-setter-return.js @@ -0,0 +1,227 @@ +/** + * @fileoverview Rule to disallow returning values from setters + * @author Milos Djermanovic + */ + +"use strict"; + +//------------------------------------------------------------------------------ +// Requirements +//------------------------------------------------------------------------------ + +const astUtils = require("./utils/ast-utils"); +const { findVariable } = require("eslint-utils"); + +//------------------------------------------------------------------------------ +// Helpers +//------------------------------------------------------------------------------ + +/** + * Determines whether the given identifier node is a reference to a global variable. + * @param {ASTNode} node `Identifier` node to check. + * @param {Scope} scope Scope to which the node belongs. + * @returns {boolean} True if the identifier is a reference to a global variable. + */ +function isGlobalReference(node, scope) { + const variable = findVariable(scope, node); + + return variable !== null && variable.scope.type === "global" && variable.defs.length === 0; +} + +/** + * Determines whether the given node is an argument of the specified global method call, at the given `index` position. + * E.g., for given `index === 1`, this function checks for `objectName.methodName(foo, node)`, where objectName is a global variable. + * @param {ASTNode} node The node to check. + * @param {Scope} scope Scope to which the node belongs. + * @param {string} objectName Name of the global object. + * @param {string} methodName Name of the method. + * @param {number} index The given position. + * @returns {boolean} `true` if the node is argument at the given position. + */ +function isArgumentOfGlobalMethodCall(node, scope, objectName, methodName, index) { + const parent = node.parent; + + return parent.type === "CallExpression" && + parent.arguments[index] === node && + parent.callee.type === "MemberExpression" && + astUtils.getStaticPropertyName(parent.callee) === methodName && + parent.callee.object.type === "Identifier" && + parent.callee.object.name === objectName && + isGlobalReference(parent.callee.object, scope); +} + +/** + * Determines whether the given node is used as a property descriptor. + * @param {ASTNode} node The node to check. + * @param {Scope} scope Scope to which the node belongs. + * @returns {boolean} `true` if the node is a property descriptor. + */ +function isPropertyDescriptor(node, scope) { + if ( + isArgumentOfGlobalMethodCall(node, scope, "Object", "defineProperty", 2) || + isArgumentOfGlobalMethodCall(node, scope, "Reflect", "defineProperty", 2) + ) { + return true; + } + + const parent = node.parent; + + if ( + parent.type === "Property" && + parent.value === node + ) { + const grandparent = parent.parent; + + if ( + grandparent.type === "ObjectExpression" && + ( + isArgumentOfGlobalMethodCall(grandparent, scope, "Object", "create", 1) || + isArgumentOfGlobalMethodCall(grandparent, scope, "Object", "defineProperties", 1) + ) + ) { + return true; + } + } + + return false; +} + +/** + * Determines whether the given function node is used as a setter function. + * @param {ASTNode} node The node to check. + * @param {Scope} scope Scope to which the node belongs. + * @returns {boolean} `true` if the node is a setter. + */ +function isSetter(node, scope) { + const parent = node.parent; + + if ( + parent.kind === "set" && + parent.value === node + ) { + + // Setter in an object literal or in a class + return true; + } + + if ( + parent.type === "Property" && + parent.value === node && + astUtils.getStaticPropertyName(parent) === "set" && + parent.parent.type === "ObjectExpression" && + isPropertyDescriptor(parent.parent, scope) + ) { + + // Setter in a property descriptor + return true; + } + + return false; +} + +/** + * Finds function's outer scope. + * @param {Scope} scope Function's own scope. + * @returns {Scope} Function's outer scope. + */ +function getOuterScope(scope) { + const upper = scope.upper; + + if (upper.type === "function-expression-name") { + return upper.upper; + } + + return upper; +} + +//------------------------------------------------------------------------------ +// Rule Definition +//------------------------------------------------------------------------------ + +module.exports = { + meta: { + type: "problem", + + docs: { + description: "disallow returning values from setters", + category: "Possible Errors", + recommended: false, + url: "https://eslint.org/docs/rules/no-setter-return" + }, + + schema: [], + + messages: { + returnsValue: "Setter cannot return a value." + } + }, + + create(context) { + let funcInfo = null; + + /** + * Creates and pushes to the stack a function info object for the given function node. + * @param {ASTNode} node The function node. + * @returns {void} + */ + function enterFunction(node) { + const outerScope = getOuterScope(context.getScope()); + + funcInfo = { + upper: funcInfo, + isSetter: isSetter(node, outerScope) + }; + } + + /** + * Pops the current function info object from the stack. + * @returns {void} + */ + function exitFunction() { + funcInfo = funcInfo.upper; + } + + /** + * Reports the given node. + * @param {ASTNode} node Node to report. + * @returns {void} + */ + function report(node) { + context.report({ node, messageId: "returnsValue" }); + } + + return { + + /* + * Function declarations cannot be setters, but we still have to track them in the `funcInfo` stack to avoid + * false positives, because a ReturnStatement node can belong to a function declaration inside a setter. + * + * Note: A previously declared function can be referenced and actually used as a setter in a property descriptor, + * but that's out of scope for this rule. + */ + FunctionDeclaration: enterFunction, + FunctionExpression: enterFunction, + ArrowFunctionExpression(node) { + enterFunction(node); + + if (funcInfo.isSetter && node.expression) { + + // { set: foo => bar } property descriptor. Report implicit return 'bar' as the equivalent for a return statement. + report(node.body); + } + }, + + "FunctionDeclaration:exit": exitFunction, + "FunctionExpression:exit": exitFunction, + "ArrowFunctionExpression:exit": exitFunction, + + ReturnStatement(node) { + + // Global returns (e.g., at the top level of a Node module) don't have `funcInfo`. + if (funcInfo && funcInfo.isSetter && node.argument) { + report(node); + } + } + }; + } +}; |