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no-unsafe-finally.js 3.90 KiB
/**
 * @fileoverview Rule to flag unsafe statements in finally block
 * @author Onur Temizkan
 */
"use strict";
//------------------------------------------------------------------------------
// Helpers
//------------------------------------------------------------------------------
const SENTINEL_NODE_TYPE_RETURN_THROW = /^(?:Program|(?:Function|Class)(?:Declaration|Expression)|ArrowFunctionExpression)$/u;
const SENTINEL_NODE_TYPE_BREAK = /^(?:Program|(?:Function|Class)(?:Declaration|Expression)|ArrowFunctionExpression|DoWhileStatement|WhileStatement|ForOfStatement|ForInStatement|ForStatement|SwitchStatement)$/u;
const SENTINEL_NODE_TYPE_CONTINUE = /^(?:Program|(?:Function|Class)(?:Declaration|Expression)|ArrowFunctionExpression|DoWhileStatement|WhileStatement|ForOfStatement|ForInStatement|ForStatement)$/u;
//------------------------------------------------------------------------------
// Rule Definition
//------------------------------------------------------------------------------
module.exports = {
    meta: {
        type: "problem",
        docs: {
            description: "disallow control flow statements in `finally` blocks",
            category: "Possible Errors",
            recommended: true,
            url: "https://eslint.org/docs/rules/no-unsafe-finally"
        schema: [],
        messages: {
            unsafeUsage: "Unsafe usage of {{nodeType}}."
    create(context) {
        /**
         * Checks if the node is the finalizer of a TryStatement
         * @param {ASTNode} node node to check.
         * @returns {boolean} - true if the node is the finalizer of a TryStatement
        function isFinallyBlock(node) {
            return node.parent.type === "TryStatement" && node.parent.finalizer === node;
        /**
         * Climbs up the tree if the node is not a sentinel node
         * @param {ASTNode} node node to check.
         * @param {string} label label of the break or continue statement
         * @returns {boolean} - return whether the node is a finally block or a sentinel node
        function isInFinallyBlock(node, label) {
            let labelInside = false;
            let sentinelNodeType;
            if (node.type === "BreakStatement" && !node.label) {
                sentinelNodeType = SENTINEL_NODE_TYPE_BREAK;
            } else if (node.type === "ContinueStatement") {
                sentinelNodeType = SENTINEL_NODE_TYPE_CONTINUE;
            } else {
                sentinelNodeType = SENTINEL_NODE_TYPE_RETURN_THROW;
            for (
                let currentNode = node;
                currentNode && !sentinelNodeType.test(currentNode.type);
                currentNode = currentNode.parent
) { if (currentNode.parent.label && label && (currentNode.parent.label.name === label.name)) { labelInside = true; } if (isFinallyBlock(currentNode)) { if (label && labelInside) { return false; } return true; } } return false; } /** * Checks whether the possibly-unsafe statement is inside a finally block. * @param {ASTNode} node node to check. * @returns {void} */ function check(node) { if (isInFinallyBlock(node, node.label)) { context.report({ messageId: "unsafeUsage", data: { nodeType: node.type }, node, line: node.loc.line, column: node.loc.column }); } } return { ReturnStatement: check, ThrowStatement: check, BreakStatement: check, ContinueStatement: check }; } };