eslint/no-redeclare Pedantic

What it does

This rule disallows redeclaring variables within the same scope, ensuring that each variable is declared only once. It helps avoid confusion and unintended behavior in code.

Why is this bad?

Redeclaring variables in the same scope can lead to unexpected behavior, overwriting existing values, and making the code harder to understand and maintain.

Examples

Examples of incorrect code for this rule:

var a = 3;
var a = 10;

Examples of correct code for this rule:

var a = 3;
a = 10;

Options

builtinGlobals

{ type: bool, default: true }

When set true, it flags redeclaring built-in globals (e.g., let Object = 1;).

How to use

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

CLI

oxlint --deny no-redeclare

Config (.oxlintrc.json)

{
  "rules": {
    "no-redeclare": "error"
  }
}

References

• Rule Source