# disallow duplicate keys in object literals (no-dupe-keys) Multiple properties with the same key in object literals can cause unexpected behavior in your application. ```js var foo = { bar: "baz", bar: "qux" }; ``` ## Rule Details This rule disallows duplicate keys in object literals. Examples of **incorrect** code for this rule: ```js /*eslint no-dupe-keys: "error"*/ var foo = { bar: "baz", bar: "qux" }; var foo = { "bar": "baz", bar: "qux" }; var foo = { 0x1: "baz", 1: "qux" }; ``` Examples of **correct** code for this rule: ```js /*eslint no-dupe-keys: "error"*/ var foo = { bar: "baz", quxx: "qux" }; ```