202 lines
8.5 KiB
Plaintext
202 lines
8.5 KiB
Plaintext
"use strict";
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Object.defineProperty(exports, "__esModule", { value: true });
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const utils_1 = require("@typescript-eslint/utils");
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const util_1 = require("../util");
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const getESLintCoreRule_1 = require("../util/getESLintCoreRule");
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const baseRule = (0, getESLintCoreRule_1.getESLintCoreRule)('no-loop-func');
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const CONSTANT_BINDINGS = new Set(['await using', 'const', 'using']);
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exports.default = (0, util_1.createRule)({
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name: 'no-loop-func',
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meta: {
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type: 'suggestion',
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// defaultOptions, -- base rule does not use defaultOptions
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deprecated: {
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deprecatedSince: '8.64.0',
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replacedBy: [
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{
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rule: {
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name: 'no-loop-func',
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url: 'https://eslint.org/docs/latest/rules/no-loop-func',
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},
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},
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],
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url: 'https://github.com/typescript-eslint/typescript-eslint/issues/12496',
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},
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docs: {
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description: 'Disallow function declarations that contain unsafe references inside loop statements',
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extendsBaseRule: true,
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},
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hasSuggestions: baseRule.meta.hasSuggestions,
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messages: baseRule.meta.messages,
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schema: [],
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},
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defaultOptions: [],
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create(context) {
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const SKIPPED_IIFE_NODES = new Set();
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/**
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* Gets the containing loop node of a specified node.
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*
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* We don't need to check nested functions, so this ignores those.
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* `Scope.through` contains references of nested functions.
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*
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* @param node An AST node to get.
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* @returns The containing loop node of the specified node, or `null`.
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*/
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function getContainingLoopNode(node) {
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for (let currentNode = node; currentNode.parent; currentNode = currentNode.parent) {
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const parent = currentNode.parent;
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switch (parent.type) {
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case utils_1.AST_NODE_TYPES.WhileStatement:
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case utils_1.AST_NODE_TYPES.DoWhileStatement:
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return parent;
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case utils_1.AST_NODE_TYPES.ForStatement:
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// `init` is outside of the loop.
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if (parent.init !== currentNode) {
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return parent;
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}
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break;
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case utils_1.AST_NODE_TYPES.ForInStatement:
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case utils_1.AST_NODE_TYPES.ForOfStatement:
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// `right` is outside of the loop.
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if (parent.right !== currentNode) {
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return parent;
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}
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break;
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case utils_1.AST_NODE_TYPES.ArrowFunctionExpression:
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case utils_1.AST_NODE_TYPES.FunctionExpression:
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case utils_1.AST_NODE_TYPES.FunctionDeclaration:
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// We don't need to check nested functions.
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// We need to check nested functions only in case of IIFE.
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if (SKIPPED_IIFE_NODES.has(parent)) {
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break;
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}
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return null;
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default:
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break;
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}
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}
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return null;
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}
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/**
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* Gets the containing loop node of a given node.
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* If the loop was nested, this returns the most outer loop.
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* @param node A node to get. This is a loop node.
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* @param excludedNode A node that the result node should not include.
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* @returns The most outer loop node.
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*/
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function getTopLoopNode(node, excludedNode) {
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const border = excludedNode ? excludedNode.range[1] : 0;
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let retv = node;
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let containingLoopNode = node;
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while (containingLoopNode && containingLoopNode.range[0] >= border) {
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retv = containingLoopNode;
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containingLoopNode = getContainingLoopNode(containingLoopNode);
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}
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return retv;
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}
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/**
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* Checks whether a given reference which refers to an upper scope's variable is
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* safe or not.
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* @param loopNode A containing loop node.
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* @param reference A reference to check.
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* @returns `true` if the reference is safe or not.
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*/
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function isSafe(loopNode, reference) {
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const variable = reference.resolved;
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const definition = variable?.defs[0];
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const declaration = definition?.parent;
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const kind = declaration?.type === utils_1.AST_NODE_TYPES.VariableDeclaration
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? declaration.kind
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: '';
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// type references are all safe
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// this only really matters for global types that haven't been configured
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if (reference.isTypeReference) {
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return true;
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}
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// Variables which are declared by `const`, `using`, or `await using` are
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// safe. They can't be reassigned, so each iteration captures a fresh one.
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if (CONSTANT_BINDINGS.has(kind)) {
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return true;
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}
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/*
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* Variables which are declared by `let` in the loop is safe.
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* It's a different instance from the next loop step's.
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*/
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if (kind === 'let' &&
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declaration &&
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declaration.range[0] > loopNode.range[0] &&
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declaration.range[1] < loopNode.range[1]) {
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return true;
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}
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/*
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* WriteReferences which exist after this border are unsafe because those
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* can modify the variable.
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*/
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const border = getTopLoopNode(loopNode, kind === 'let' ? declaration : null).range[0];
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/**
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* Checks whether a given reference is safe or not.
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* The reference is every reference of the upper scope's variable we are
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* looking now.
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*
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* It's safe if the reference matches one of the following condition.
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* - is readonly.
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* - doesn't exist inside a local function and after the border.
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*
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* @param upperRef A reference to check.
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* @returns `true` if the reference is safe.
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*/
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function isSafeReference(upperRef) {
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const id = upperRef.identifier;
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return (!upperRef.isWrite() ||
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(variable?.scope.variableScope === upperRef.from.variableScope &&
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id.range[0] < border));
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}
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return variable?.references.every(isSafeReference) ?? false;
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}
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/**
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* Reports functions which match the following condition:
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* - has a loop node in ancestors.
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* - has any references which refers to an unsafe variable.
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*
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* @param node The AST node to check.
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*/
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function checkForLoops(node) {
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const loopNode = getContainingLoopNode(node);
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if (!loopNode) {
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return;
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}
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const references = context.sourceCode.getScope(node).through;
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if (!(node.async || node.generator) && isIIFE(node)) {
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const isFunctionExpression = node.type === utils_1.AST_NODE_TYPES.FunctionExpression;
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// Check if the function is referenced elsewhere in the code
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const isFunctionReferenced = isFunctionExpression && node.id
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? references.some(r => r.identifier.name === node.id?.name)
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: false;
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if (!isFunctionReferenced) {
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SKIPPED_IIFE_NODES.add(node);
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return;
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}
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}
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const unsafeRefs = references
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.filter(r => r.resolved && !isSafe(loopNode, r))
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.map(r => r.identifier.name);
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if (unsafeRefs.length > 0) {
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context.report({
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node,
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messageId: 'unsafeRefs',
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data: { varNames: `'${unsafeRefs.join("', '")}'` },
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});
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}
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}
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return {
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ArrowFunctionExpression: checkForLoops,
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FunctionDeclaration: checkForLoops,
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FunctionExpression: checkForLoops,
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};
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},
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});
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function isIIFE(node) {
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return (node.parent.type === utils_1.AST_NODE_TYPES.CallExpression &&
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node.parent.callee === node);
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}
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