Why is this an issue?

TypeScript provides both numeric and string-based enums. Members of enums can be assigned strings, numbers, both, or none, which default to numbers starting from zero. Although it is possble to mix the types of enum member values, it is generally considered confusing and a bad practice.

Enum members should be consistently assigned values of the same type, that is, strings or numbers.

How to fix it

Either assign all enum members with values of the same type or none of them.

Code examples

Noncompliant code example

enum Color {
    Red, // 0 by default
    Green = 1,
    Blue = "blue"
}

Compliant solution

enum Color {
    Red = "red",
    Green = "green",
    Blue = "blue"
}

Noncompliant code example

enum Status {
    SYN = 0,
    SYN_ACK,
    ACK = "ack"
}

Compliant solution

enum Direction {
    SYN,
    SYN_ACK,
    ACK
}

Resources

Documentation