2 * @fileoverview Rule to disallow returning values from Promise executor functions
3 * @author Milos Djermanovic
8 //------------------------------------------------------------------------------
10 //------------------------------------------------------------------------------
12 const { findVariable } = require("eslint-utils");
14 //------------------------------------------------------------------------------
16 //------------------------------------------------------------------------------
18 const functionTypesToCheck = new Set(["ArrowFunctionExpression", "FunctionExpression"]);
21 * Determines whether the given identifier node is a reference to a global variable.
22 * @param {ASTNode} node `Identifier` node to check.
23 * @param {Scope} scope Scope to which the node belongs.
24 * @returns {boolean} True if the identifier is a reference to a global variable.
26 function isGlobalReference(node, scope) {
27 const variable = findVariable(scope, node);
29 return variable !== null && variable.scope.type === "global" && variable.defs.length === 0;
33 * Finds function's outer scope.
34 * @param {Scope} scope Function's own scope.
35 * @returns {Scope} Function's outer scope.
37 function getOuterScope(scope) {
38 const upper = scope.upper;
40 if (upper.type === "function-expression-name") {
47 * Determines whether the given function node is used as a Promise executor.
48 * @param {ASTNode} node The node to check.
49 * @param {Scope} scope Function's own scope.
50 * @returns {boolean} `true` if the node is a Promise executor.
52 function isPromiseExecutor(node, scope) {
53 const parent = node.parent;
55 return parent.type === "NewExpression" &&
56 parent.arguments[0] === node &&
57 parent.callee.type === "Identifier" &&
58 parent.callee.name === "Promise" &&
59 isGlobalReference(parent.callee, getOuterScope(scope));
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64 //------------------------------------------------------------------------------
71 description: "disallow returning values from Promise executor functions",
72 category: "Possible Errors",
74 url: "https://eslint.org/docs/rules/no-promise-executor-return"
80 returnsValue: "Return values from promise executor functions cannot be read."
89 * Reports the given node.
90 * @param {ASTNode} node Node to report.
93 function report(node) {
94 context.report({ node, messageId: "returnsValue" });
99 onCodePathStart(_, node) {
102 shouldCheck: functionTypesToCheck.has(node.type) && isPromiseExecutor(node, context.getScope())
105 if (funcInfo.shouldCheck && node.type === "ArrowFunctionExpression" && node.expression) {
111 funcInfo = funcInfo.upper;
114 ReturnStatement(node) {
115 if (funcInfo.shouldCheck && node.argument) {