Duplicate parameter names¶
ID: js/duplicate-parameter-name
Kind: problem
Security severity:
Severity: error
Precision: very-high
Tags:
- reliability
- correctness
Query suites:
- javascript-security-and-quality.qls
Click to see the query in the CodeQL repository
In non-strict mode, JavaScript allows a function to have several parameters with the same name, where later parameters shadow earlier parameters. This is an error-prone feature which makes code hard to understand and should be avoided.
Recommendation¶
Rename the parameters to have different names.
Example¶
In the following example, function f has two parameters named x, the second one presumably being a typo for y. Since no parameter y is declared, the use of y in the body of f refers to a global variable of that name, if it exists.
function f(x, x) {
return x+y;
}
Duplicate parameter names are illegal in strict mode.
References¶
Ecma International, ECMAScript Language Definition, 5.1 Edition, Annex C. ECMA, 2011.