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Direktori : /var/www/html/node_modules/eslint/lib/rules/ |
Current File : /var/www/html/node_modules/eslint/lib/rules/no-lone-blocks.js |
/** * @fileoverview Rule to flag blocks with no reason to exist * @author Brandon Mills */ "use strict"; //------------------------------------------------------------------------------ // Rule Definition //------------------------------------------------------------------------------ /** @type {import('../shared/types').Rule} */ module.exports = { meta: { type: "suggestion", docs: { description: "disallow unnecessary nested blocks", recommended: false, url: "https://eslint.org/docs/rules/no-lone-blocks" }, schema: [], messages: { redundantBlock: "Block is redundant.", redundantNestedBlock: "Nested block is redundant." } }, create(context) { // A stack of lone blocks to be checked for block-level bindings const loneBlocks = []; let ruleDef; /** * Reports a node as invalid. * @param {ASTNode} node The node to be reported. * @returns {void} */ function report(node) { const messageId = node.parent.type === "BlockStatement" || node.parent.type === "StaticBlock" ? "redundantNestedBlock" : "redundantBlock"; context.report({ node, messageId }); } /** * Checks for any occurrence of a BlockStatement in a place where lists of statements can appear * @param {ASTNode} node The node to check * @returns {boolean} True if the node is a lone block. */ function isLoneBlock(node) { return node.parent.type === "BlockStatement" || node.parent.type === "StaticBlock" || node.parent.type === "Program" || // Don't report blocks in switch cases if the block is the only statement of the case. node.parent.type === "SwitchCase" && !(node.parent.consequent[0] === node && node.parent.consequent.length === 1); } /** * Checks the enclosing block of the current node for block-level bindings, * and "marks it" as valid if any. * @returns {void} */ function markLoneBlock() { if (loneBlocks.length === 0) { return; } const block = context.getAncestors().pop(); if (loneBlocks[loneBlocks.length - 1] === block) { loneBlocks.pop(); } } // Default rule definition: report all lone blocks ruleDef = { BlockStatement(node) { if (isLoneBlock(node)) { report(node); } } }; // ES6: report blocks without block-level bindings, or that's only child of another block if (context.parserOptions.ecmaVersion >= 6) { ruleDef = { BlockStatement(node) { if (isLoneBlock(node)) { loneBlocks.push(node); } }, "BlockStatement:exit"(node) { if (loneBlocks.length > 0 && loneBlocks[loneBlocks.length - 1] === node) { loneBlocks.pop(); report(node); } else if ( ( node.parent.type === "BlockStatement" || node.parent.type === "StaticBlock" ) && node.parent.body.length === 1 ) { report(node); } } }; ruleDef.VariableDeclaration = function(node) { if (node.kind === "let" || node.kind === "const") { markLoneBlock(); } }; ruleDef.FunctionDeclaration = function() { if (context.getScope().isStrict) { markLoneBlock(); } }; ruleDef.ClassDeclaration = markLoneBlock; } return ruleDef; } };