disallow duplicate keys in object literals (no-dupe-keys)
The "extends": "eslint:recommended" property in a configuration file enables this rule.
Multiple properties with the same key in object literals can cause unexpected behavior in your application.
var foo = {
    bar: "baz",
    bar: "qux"
};
Rule Details
This rule disallows duplicate keys in object literals.
Examples of incorrect code for this rule:
/*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:
/*eslint no-dupe-keys: "error"*/
var foo = {
    bar: "baz",
    quxx: "qux"
};
Version
This rule was introduced in ESLint 0.0.9.
Resources
    © OpenJS Foundation and other contributors
Licensed under the MIT License.
    https://eslint.org/docs/rules/no-dupe-keys