eslint/no-param-reassign Restriction ​
What it does ​
Disallow reassigning function parameters or, optionally, their properties.
Why is this bad? ​
Reassigning parameters can lead to unexpected behavior, especially when relying on the original arguments passed into the function. Mutating parameter properties can be similarly surprising and harder to reason about.
Examples ​
javascript
function foo(bar) {
bar = 1;
}
function baz(qux) {
qux.prop = 2; // when `props` option is enabled
}Configuration ​
This rule accepts a configuration object with the following properties:
ignorePropertyModificationsFor ​
type: string[]
default: []
An array of parameter names whose property modifications should be ignored.
ignorePropertyModificationsForRegex ​
type: string[]
An array of regex patterns (as strings) for parameter names whose property modifications should be ignored. Note that this uses Rust regex syntax and so may not have all features available to JavaScript regexes.
props ​
type: boolean
default: false
When true, also check for modifications to properties of parameters.
How to use ​
To enable this rule in the CLI or using the config file, you can use:
bash
oxlint --deny no-param-reassignjson
{
"rules": {
"no-param-reassign": "error"
}
}