Permalink
Cannot retrieve contributors at this time
133 lines (114 sloc)
4.66 KB
Name already in use
A tag already exists with the provided branch name. Many Git commands accept both tag and branch names, so creating this branch may cause unexpected behavior. Are you sure you want to create this branch?
codeql-action/node_modules/eslint/lib/rules/for-direction.js
Go to fileThis commit does not belong to any branch on this repository, and may belong to a fork outside of the repository.
This file contains bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
/** | |
* @fileoverview enforce "for" loop update clause moving the counter in the right direction.(for-direction) | |
* @author Aladdin-ADD<hh_2013@foxmail.com> | |
*/ | |
"use strict"; | |
//------------------------------------------------------------------------------ | |
// Requirements | |
//------------------------------------------------------------------------------ | |
const { getStaticValue } = require("@eslint-community/eslint-utils"); | |
//------------------------------------------------------------------------------ | |
// Rule Definition | |
//------------------------------------------------------------------------------ | |
/** @type {import('../shared/types').Rule} */ | |
module.exports = { | |
meta: { | |
type: "problem", | |
docs: { | |
description: "Enforce \"for\" loop update clause moving the counter in the right direction", | |
recommended: true, | |
url: "https://eslint.org/docs/latest/rules/for-direction" | |
}, | |
fixable: null, | |
schema: [], | |
messages: { | |
incorrectDirection: "The update clause in this loop moves the variable in the wrong direction." | |
} | |
}, | |
create(context) { | |
const { sourceCode } = context; | |
/** | |
* report an error. | |
* @param {ASTNode} node the node to report. | |
* @returns {void} | |
*/ | |
function report(node) { | |
context.report({ | |
node, | |
messageId: "incorrectDirection" | |
}); | |
} | |
/** | |
* check the right side of the assignment | |
* @param {ASTNode} update UpdateExpression to check | |
* @param {int} dir expected direction that could either be turned around or invalidated | |
* @returns {int} return dir, the negated dir, or zero if the counter does not change or the direction is not clear | |
*/ | |
function getRightDirection(update, dir) { | |
const staticValue = getStaticValue(update.right, sourceCode.getScope(update)); | |
if (staticValue && ["bigint", "boolean", "number"].includes(typeof staticValue.value)) { | |
const sign = Math.sign(Number(staticValue.value)) || 0; // convert NaN to 0 | |
return dir * sign; | |
} | |
return 0; | |
} | |
/** | |
* check UpdateExpression add/sub the counter | |
* @param {ASTNode} update UpdateExpression to check | |
* @param {string} counter variable name to check | |
* @returns {int} if add return 1, if sub return -1, if nochange, return 0 | |
*/ | |
function getUpdateDirection(update, counter) { | |
if (update.argument.type === "Identifier" && update.argument.name === counter) { | |
if (update.operator === "++") { | |
return 1; | |
} | |
if (update.operator === "--") { | |
return -1; | |
} | |
} | |
return 0; | |
} | |
/** | |
* check AssignmentExpression add/sub the counter | |
* @param {ASTNode} update AssignmentExpression to check | |
* @param {string} counter variable name to check | |
* @returns {int} if add return 1, if sub return -1, if nochange, return 0 | |
*/ | |
function getAssignmentDirection(update, counter) { | |
if (update.left.name === counter) { | |
if (update.operator === "+=") { | |
return getRightDirection(update, 1); | |
} | |
if (update.operator === "-=") { | |
return getRightDirection(update, -1); | |
} | |
} | |
return 0; | |
} | |
return { | |
ForStatement(node) { | |
if (node.test && node.test.type === "BinaryExpression" && node.test.left.type === "Identifier" && node.update) { | |
const counter = node.test.left.name; | |
const operator = node.test.operator; | |
const update = node.update; | |
let wrongDirection; | |
if (operator === "<" || operator === "<=") { | |
wrongDirection = -1; | |
} else if (operator === ">" || operator === ">=") { | |
wrongDirection = 1; | |
} else { | |
return; | |
} | |
if (update.type === "UpdateExpression") { | |
if (getUpdateDirection(update, counter) === wrongDirection) { | |
report(node); | |
} | |
} else if (update.type === "AssignmentExpression" && getAssignmentDirection(update, counter) === wrongDirection) { | |
report(node); | |
} | |
} | |
} | |
}; | |
} | |
}; |