eslint-plugin-sonarjs
Version:
SonarJS rules for ESLint
158 lines (157 loc) • 6.18 kB
JavaScript
;
/*
* SonarQube JavaScript Plugin
* Copyright (C) 2011-2025 SonarSource Sàrl
* mailto:info AT sonarsource DOT com
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the Sonar Source-Available License Version 1, as published by SonarSource SA.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
* See the Sonar Source-Available License for more details.
*
* You should have received a copy of the Sonar Source-Available License
* along with this program; if not, see https://sonarsource.com/license/ssal/
*/
// https://sonarsource.github.io/rspec/#/rspec/S2310/javascript
var __createBinding = (this && this.__createBinding) || (Object.create ? (function(o, m, k, k2) {
if (k2 === undefined) k2 = k;
var desc = Object.getOwnPropertyDescriptor(m, k);
if (!desc || ("get" in desc ? !m.__esModule : desc.writable || desc.configurable)) {
desc = { enumerable: true, get: function() { return m[k]; } };
}
Object.defineProperty(o, k2, desc);
}) : (function(o, m, k, k2) {
if (k2 === undefined) k2 = k;
o[k2] = m[k];
}));
var __setModuleDefault = (this && this.__setModuleDefault) || (Object.create ? (function(o, v) {
Object.defineProperty(o, "default", { enumerable: true, value: v });
}) : function(o, v) {
o["default"] = v;
});
var __importStar = (this && this.__importStar) || (function () {
var ownKeys = function(o) {
ownKeys = Object.getOwnPropertyNames || function (o) {
var ar = [];
for (var k in o) if (Object.prototype.hasOwnProperty.call(o, k)) ar[ar.length] = k;
return ar;
};
return ownKeys(o);
};
return function (mod) {
if (mod && mod.__esModule) return mod;
var result = {};
if (mod != null) for (var k = ownKeys(mod), i = 0; i < k.length; i++) if (k[i] !== "default") __createBinding(result, mod, k[i]);
__setModuleDefault(result, mod);
return result;
};
})();
Object.defineProperty(exports, "__esModule", { value: true });
exports.rule = void 0;
const index_js_1 = require("../helpers/index.js");
const meta = __importStar(require("./generated-meta.js"));
exports.rule = {
meta: (0, index_js_1.generateMeta)(meta),
create(context) {
function checkLoop(updateNode, extractCounters, loopBody) {
const counters = [];
extractCounters(updateNode, counters);
for (const counter of counters) {
checkCounter(counter, loopBody);
}
}
function checkCounter(counter, block) {
const variable = (0, index_js_1.getVariableFromName)(context, counter.name, block);
if (!variable) {
return;
}
for (const ref of variable.references) {
if (ref.isWrite() && isUsedInsideBody(ref.identifier, block)) {
if (isIntentionalSkipAhead(ref.identifier, block)) {
continue;
}
(0, index_js_1.report)(context, {
node: ref.identifier,
message: `Remove this assignment of "${counter.name}".`,
}, [(0, index_js_1.toSecondaryLocation)(counter, 'Counter variable update')]);
}
}
}
return {
'ForStatement > BlockStatement': (node) => {
const forLoop = (0, index_js_1.getParent)(context, node);
if (forLoop.update) {
checkLoop(forLoop.update, collectCountersFor, node);
}
},
// Note: for-of and for-in loops are not checked because reassigning
// the iterator variable does not affect loop iteration (the iterator
// protocol controls progression, not the variable value)
};
},
};
function collectCountersFor(updateExpression, counters) {
let counter = undefined;
if (updateExpression.type === 'AssignmentExpression') {
counter = updateExpression.left;
}
else if (updateExpression.type === 'UpdateExpression') {
counter = updateExpression.argument;
}
else if (updateExpression.type === 'SequenceExpression') {
for (const e of updateExpression.expressions) {
collectCountersFor(e, counters);
}
}
if (counter?.type === 'Identifier') {
counters.push(counter);
}
}
/**
* Checks if a loop counter modification is an intentional skip-ahead pattern
* (UpdateExpression or compound assignment) rather than a simple assignment.
* Modifications in nested for-loop update clauses are not considered skip-ahead.
*/
function isIntentionalSkipAhead(id, outerLoopBody) {
if (isInNestedForLoopUpdate(id, outerLoopBody)) {
return false;
}
const parent = (0, index_js_1.getNodeParent)(id);
if (parent?.type === 'UpdateExpression') {
return true;
}
if (parent?.type === 'AssignmentExpression' && parent.operator !== '=') {
return true;
}
return false;
}
function isUsedInsideBody(id, loopBody) {
const bodyRange = loopBody.range;
return id.range && bodyRange && id.range[0] > bodyRange[0] && id.range[1] < bodyRange[1];
}
function isInNestedForLoopUpdate(id, outerLoopBody) {
let node = id;
let parent = (0, index_js_1.getNodeParent)(node);
while (parent) {
// Stop if we've reached the outer loop body
if (parent === outerLoopBody) {
return false;
}
// Check if we're in a nested for-loop's update clause
if (parent.type === 'ForStatement' && parent.update) {
const updateRange = parent.update.range;
if (updateRange &&
id.range &&
id.range[0] >= updateRange[0] &&
id.range[1] <= updateRange[1]) {
return true;
}
}
node = parent;
parent = (0, index_js_1.getNodeParent)(node);
}
return false;
}