no-negated-condition.js
2.32 KB
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
/**
* @fileoverview Rule to disallow a negated condition
* @author Alberto Rodríguez
* @copyright 2015 Alberto Rodríguez. All rights reserved.
* See LICENSE file in root directory for full license.
*/
"use strict";
//------------------------------------------------------------------------------
// Rule Definition
//------------------------------------------------------------------------------
module.exports = function(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": function(node) {
if (!hasElseWithoutCondition(node)) {
return;
}
if (isNegatedIf(node)) {
context.report(node, "Unexpected negated condition.");
}
},
"ConditionalExpression": function(node) {
if (isNegatedIf(node)) {
context.report(node, "Unexpected negated condition.");
}
}
};
};
module.exports.schema = [];