no-dupe-args

When two parameters have the same name, the name refers to the last one. You can only reach the argument passed for the first one through arguments. It's nearly always a typo or a copy-paste mistake.

In strict mode, in modules and in arrow functions this is already a syntax error. The rule catches it in the scripts where it isn't, such as a .cjs file without "use strict".

This rule is on by default in JavaScript files. It's off in TypeScript files, where TypeScript reports the same mistake.

Configure

On by default as an error. To turn it off:

[lint.rules]
"no-dupe-args" = "off" # or "warn"

Examples

Reported, in a .cjs file:

function resize(width, height, width) {
  return width * height;
}

Not reported:

function resize(width, height, depth) {
  return width * height * depth;
}