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
75
76
77
78
79
80
81
82
83
84
85
|
/**
* @fileoverview Disallow reassignment of function parameters.
* @author Nat Burns
* @copyright 2014 Nat Burns. All rights reserved.
*/
"use strict";
//------------------------------------------------------------------------------
// Rule Definition
//------------------------------------------------------------------------------
module.exports = function(context) {
//--------------------------------------------------------------------------
// Helpers
//--------------------------------------------------------------------------
/**
* Finds the declaration for a given variable by name, searching up the scope tree.
* @param {Scope} scope The scope in which to search.
* @param {String} name The name of the variable.
* @returns {Variable} The declaration information for the given variable, or null if no declaration was found.
*/
function findDeclaration(scope, name) {
var variables = scope.variables;
for (var i = 0; i < variables.length; i++) {
if (variables[i].name === name) {
return variables[i];
}
}
if (scope.upper) {
return findDeclaration(scope.upper, name);
} else {
return null;
}
}
/**
* Determines if a given variable is declared as a function parameter.
* @param {Variable} variable The variable declaration.
* @returns {boolean} True if the variable is a function parameter, false otherwise.
*/
function isParameter(variable) {
var defs = variable.defs;
for (var i = 0; i < defs.length; i++) {
if (defs[i].type === "Parameter") {
return true;
}
}
return false;
}
/**
* Checks whether a given node is an assignment to a function parameter.
* If so, a linting error will be reported.
* @param {ASTNode} node The node to check.
* @param {String} name The name of the variable being assigned to.
* @returns {void}
*/
function checkParameter(node, name) {
var declaration = findDeclaration(context.getScope(), name);
if (declaration && isParameter(declaration)) {
context.report(node, "Assignment to function parameter '{{name}}'.", { name: name });
}
}
//--------------------------------------------------------------------------
// Public
//--------------------------------------------------------------------------
return {
"AssignmentExpression": function(node) {
checkParameter(node, node.left.name);
},
"UpdateExpression": function(node) {
checkParameter(node, node.argument.name);
}
};
};
|
