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eslint/no-dupe-class-members Correctness

✅ This rule is turned on by default.

What it does

Disallow duplicate class members.

This rule can be disabled for TypeScript code, as the TypeScript compiler enforces this check.

Why is this bad?

If there are declarations of the same name in class members, the last declaration overwrites other declarations silently. It can cause unexpected behaviors.

Examples

Examples of incorrect code for this rule:

class A {
  foo() {
    console.log("foo");
  }
  foo = 123;
}
let a = new A();
a.foo(); // Uncaught TypeError: a.foo is not a function

Examples of correct code for this rule:

class A {
  foo() {
    console.log("foo");
  }
}
let a = new A();
a.foo();

How to use

To enable this rule using the config file or in the CLI, you can use:

Config (.oxlintrc.json)

{
  "rules": {
    "no-dupe-class-members": "error"
  }
}

Config (oxlint.config.ts)

import { defineConfig } from "oxlint";

export default defineConfig({
  rules: {
    "no-dupe-class-members": "error",
  },
});

CLI

oxlint --deny no-dupe-class-members

Version

This rule was added in v0.0.3.

References

• Rule Source
• Upstream rule docs
• Open rule in Oxc Playground