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codeql-action/node_modules/eslint/lib/rules/no-lone-blocks.js
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/** | |
* @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/latest/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; | |
const sourceCode = context.sourceCode; | |
/** | |
* 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. | |
* @param {ASTNode} node The current node to check. | |
* @returns {void} | |
*/ | |
function markLoneBlock(node) { | |
if (loneBlocks.length === 0) { | |
return; | |
} | |
const block = node.parent; | |
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.languageOptions.ecmaVersion >= 2015) { | |
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(node); | |
} | |
}; | |
ruleDef.FunctionDeclaration = function(node) { | |
if (sourceCode.getScope(node).isStrict) { | |
markLoneBlock(node); | |
} | |
}; | |
ruleDef.ClassDeclaration = markLoneBlock; | |
} | |
return ruleDef; | |
} | |
}; |