@typescript-eslint/no-duplicate-enum-values

You can't tell two enum members with the same value apart at runtime. Status.Active === Status.Enabled is true, a switch only ever reaches the first case, and for numbers the reverse lookup Status[1] gives only the last name.

The rule only compares values written as a number, a string or a template without ${}, with or without a + or - sign. It skips members without a value and computed values.

This rule is on by default in TypeScript files.

Configure#

On by default as a warning. To turn it off:

[lint.rules]
"@typescript-eslint/no-duplicate-enum-values" = "off" # or "error"

Examples#

enum Status {
  Active = 1,
  Enabled = 1,
}

enum Color {
  Red = "red",
  Crimson = "red",
}

enum Status {
  Active = 1,
  Disabled = 2,
}

enum Color {
  Red = "red",
  Crimson = "crimson",
}

A value that TypeScript fills in isn't compared. Here Third is 1 as well:

enum Rank {
  First = 1,
  Second = 0,
  Third,
}