--- description: 'Disallow enums from having both number and string members.' --- import Tabs from '@theme/Tabs'; import TabItem from '@theme/TabItem'; > πŸ›‘ This file is source code, not the primary documentation location! πŸ›‘ > > See **https://typescript-eslint.io/rules/no-mixed-enums** for documentation. TypeScript enums are allowed to assign numeric or string values to their members. Most enums contain either all numbers or all strings, but in theory you can mix-and-match within the same enum. Mixing enum member types is generally considered confusing and a bad practice. ## Examples ```ts enum Status { Unknown, Closed = 1, Open = 'open', } ``` ```ts enum Status { Unknown = 0, Closed = 1, Open = 2, } ``` ```ts enum Status { Unknown, Closed, Open, } ``` ```ts enum Status { Unknown = 'unknown', Closed = 'closed', Open = 'open', } ``` ## Iteration Pitfalls of Mixed Enum Member Values Enum values may be iterated over using `Object.entries`/`Object.keys`/`Object.values`. If all enum members are strings, the number of items will match the number of enum members: ```ts enum Status { Closed = 'closed', Open = 'open', } // ['closed', 'open'] Object.values(Status); ``` But if the enum contains members that are initialized with numbers -including implicitly initialized numbersβ€” then iteration over that enum will include those numbers as well: ```ts enum Status { Unknown, Closed = 1, Open = 'open', } // ["Unknown", "Closed", 0, 1, "open"] Object.values(Status); ``` ## When Not To Use It If you don't mind the confusion of mixed enum member values and don't iterate over enums, you can safely disable this rule.