eslint-plugin-sonarjs
Version:
SonarJS rules for ESLint
120 lines (119 loc) • 5.48 kB
JavaScript
;
/*
* eslint-plugin-sonarjs
* Copyright (C) 2018-2021 SonarSource SA
* mailto:info AT sonarsource DOT com
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU Lesser General Public
* License as published by the Free Software Foundation; either
* version 3 of the License, or (at your option) any later version.
*
* 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 GNU
* Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public License
* along with this program; if not, write to the Free Software Foundation,
* Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
*/
// https://sonarsource.github.io/rspec/#/rspec/S1488
var __importDefault = (this && this.__importDefault) || function (mod) {
return (mod && mod.__esModule) ? mod : { "default": mod };
};
const nodes_1 = require("../utils/nodes");
const docs_url_1 = __importDefault(require("../utils/docs-url"));
const rule = {
defaultOptions: [],
meta: {
messages: {
doImmediateAction: 'Immediately {{action}} this expression instead of assigning it to the temporary variable "{{variable}}".',
},
schema: [],
type: 'suggestion',
docs: {
description: 'Local variables should not be declared and then immediately returned or thrown',
recommended: 'recommended',
url: (0, docs_url_1.default)(__filename),
},
fixable: 'code',
},
create(context) {
return {
BlockStatement(node) {
processStatements(node, node.body);
},
SwitchCase(node) {
processStatements(node, node.consequent);
},
};
function processStatements(node, statements) {
if (statements.length > 1) {
const last = statements[statements.length - 1];
const returnedIdentifier = getOnlyReturnedVariable(last);
const lastButOne = statements[statements.length - 2];
const declaredIdentifier = getOnlyDeclaredVariable(lastButOne);
if (returnedIdentifier && declaredIdentifier) {
const sameVariable = getVariables(node, context).find(variable => {
return (variable.references.find(ref => ref.identifier === returnedIdentifier) !==
undefined &&
variable.references.find(ref => ref.identifier === declaredIdentifier.id) !==
undefined);
});
// there must be only one "read" - in `return` or `throw`
if (sameVariable && sameVariable.references.filter(ref => ref.isRead()).length === 1) {
context.report({
messageId: 'doImmediateAction',
data: {
action: (0, nodes_1.isReturnStatement)(last) ? 'return' : 'throw',
variable: returnedIdentifier.name,
},
node: declaredIdentifier.init,
fix: fixer => fix(fixer, last, lastButOne, declaredIdentifier.init, returnedIdentifier),
});
}
}
}
}
// eslint-disable-next-line max-params
function fix(fixer, last, lastButOne, expressionToReturn, returnedExpression) {
const expressionText = context.sourceCode.getText(expressionToReturn);
const rangeToRemoveStart = lastButOne.range[0];
const commentsBetweenStatements = context.sourceCode.getCommentsAfter(lastButOne);
const rangeToRemoveEnd = commentsBetweenStatements.length > 0
? commentsBetweenStatements[0].range[0]
: last.range[0];
return [
fixer.removeRange([rangeToRemoveStart, rangeToRemoveEnd]),
fixer.replaceText(returnedExpression, expressionText),
];
}
function getOnlyReturnedVariable(node) {
return ((0, nodes_1.isReturnStatement)(node) || (0, nodes_1.isThrowStatement)(node)) &&
node.argument &&
(0, nodes_1.isIdentifier)(node.argument)
? node.argument
: undefined;
}
function getOnlyDeclaredVariable(node) {
if ((0, nodes_1.isVariableDeclaration)(node) && node.declarations.length === 1) {
const { id, init } = node.declarations[0];
if ((0, nodes_1.isIdentifier)(id) && init && !id.typeAnnotation) {
return { id, init };
}
}
return undefined;
}
function getVariables(node, context) {
const { variableScope, variables: currentScopeVariables } = context.sourceCode.getScope(node);
if (variableScope === context.sourceCode.getScope(node)) {
return currentScopeVariables;
}
else {
return currentScopeVariables.concat(variableScope.variables);
}
}
},
};
module.exports = rule;