83 lines
2.6 KiB
JavaScript
83 lines
2.6 KiB
JavaScript
/**
|
|
* @fileoverview Rule to disallow a negated condition
|
|
* @author Alberto Rodríguez
|
|
*/
|
|
"use strict";
|
|
|
|
//------------------------------------------------------------------------------
|
|
// Rule Definition
|
|
//------------------------------------------------------------------------------
|
|
|
|
module.exports = {
|
|
meta: {
|
|
docs: {
|
|
description: "disallow negated conditions",
|
|
category: "Stylistic Issues",
|
|
recommended: false
|
|
},
|
|
|
|
schema: []
|
|
},
|
|
|
|
create(context) {
|
|
|
|
/**
|
|
* Determines if a given node is an if-else without a condition on the else
|
|
* @param {ASTNode} node The node to check.
|
|
* @returns {boolean} True if the node has an else without an if.
|
|
* @private
|
|
*/
|
|
function hasElseWithoutCondition(node) {
|
|
return node.alternate && node.alternate.type !== "IfStatement";
|
|
}
|
|
|
|
/**
|
|
* Determines if a given node is a negated unary expression
|
|
* @param {Object} test The test object to check.
|
|
* @returns {boolean} True if the node is a negated unary expression.
|
|
* @private
|
|
*/
|
|
function isNegatedUnaryExpression(test) {
|
|
return test.type === "UnaryExpression" && test.operator === "!";
|
|
}
|
|
|
|
/**
|
|
* Determines if a given node is a negated binary expression
|
|
* @param {Test} test The test to check.
|
|
* @returns {boolean} True if the node is a negated binary expression.
|
|
* @private
|
|
*/
|
|
function isNegatedBinaryExpression(test) {
|
|
return test.type === "BinaryExpression" &&
|
|
(test.operator === "!=" || test.operator === "!==");
|
|
}
|
|
|
|
/**
|
|
* Determines if a given node has a negated if expression
|
|
* @param {ASTNode} node The node to check.
|
|
* @returns {boolean} True if the node has a negated if expression.
|
|
* @private
|
|
*/
|
|
function isNegatedIf(node) {
|
|
return isNegatedUnaryExpression(node.test) || isNegatedBinaryExpression(node.test);
|
|
}
|
|
|
|
return {
|
|
IfStatement(node) {
|
|
if (!hasElseWithoutCondition(node)) {
|
|
return;
|
|
}
|
|
|
|
if (isNegatedIf(node)) {
|
|
context.report({ node, message: "Unexpected negated condition." });
|
|
}
|
|
},
|
|
ConditionalExpression(node) {
|
|
if (isNegatedIf(node)) {
|
|
context.report({ node, message: "Unexpected negated condition." });
|
|
}
|
|
}
|
|
};
|
|
}
|
|
};
|